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Fluoride-vitamin supplements: effects on dental caries and fluorosis when used in areas with suboptimum fluoride in the water supply
Supplemental fluoride regimens were provided to infants residing in suboptimal fluoride areas. These regimens resulted in additional protection against dental caries beyond that provided by the fluoridated water and a cosmetically acceptable increase in dental fluorosis.
Fluoride-vitamin supplements: effects on dental caries and fluorosis when used in areas with suboptimum fluoride in the water supply
David K. Hennon, DDS, MSD George K. Stookey, MSD, PhD Bradley B. Beiswanger, DDS, India n a p o lis
Drinking water containing an optimum amount of fluoride has been recognized as an effective method to decrease the incidence of dental caries. Fluoridation of municipal water supplies is often acknowledged as a basic public health measure since it is highly effective, safe, and economical and since persons acquire the benefits without conscious effort. In 1974, about half the US popu lation, or more than 100 million persons, were served by water supplies containing an optimum concentration of fluoride either naturally or me chanically added.1 Fluoride supplements, alone or in vitamin combinations, are effective in decreasing the inci dence of dental caries in children living in areas with no fluoride in the water supply.2-6 However, no studies have been reported that evaluated the anticariogenic benefits of fluoride supplements used in areas containing suboptimum amounts of fluoride in the water (that is, 0.6 to 0.8 ppm com pared with the optimum value of 1.0 ppm for In
diana). For a discussion of how optimum fluoride levels in drinking water are established for differ ent geographic areas, the reader is referred to the work of Galagan and Vermillion.7 It was questioned whether a fluoride supple ment would give added protection against dental caries in these areas and whether the additional fluoride would cause any significant increase in dental fluorosis. The answer to these questions are important since the A D A Council on Dental Therapeutics8 recommends that the supplemental fluoride dosage be decreased as the level of fluoride in drinking water increases from 0.0 to 0.7 ppm. If extra fluoride could be given in a fixed, convenient dosage form in all areas where water contained 0.7 ppm fluoride or less, the problem of calculating and titrating individual fluoride dos ages would be eliminated. Thus, physicians and dentists may be more likely to prescribe fluoride supplements for infants and children who could benefit from the additional fluoride. JADA, Vol. 95, November 1977 ■ 965
M e th o d s a n d m a te ria ls
A total of 456 infants, 1 to 14 months of age, living in eight different Indiana communities having 0.6 to 0.8 ppm fluoride in their water supplies, were scheduled and examined initially for this project. In Indiana, the water fluoride content of all com munities is surveyed periodically by the Indiana State Board of Health. These data (not published) were used to select the communities for inclusion in this study. A list of children in the desired age range was obtained by screening birth records for each of the cities through the cooperation of the Indiana State Board of Health. A letter explaining the purpose and procedures of this program and a permission form were sent to the parents. Only those children for whom signed parental consent forms were returned were enrolled in the study. The parents of the participants could withdraw them from the program at any time. Physicians and dentists in each of these com munities received the same information letter that was sent to the parents. Whenever possible, the program was also explained to physicians and dentists at meetings of their professional societies. Special meetings to explain the program were held with the administrative officials in each city; the newspapers in each area were also in formed. Each child was assigned to one of three study groups by systematic allocation after stratifica tion by sex and age. Neither the clinical examiner (D .K .H .) for dental caries and fluorosis, nor the patients had knowledge of group assignments or product codes. Siblings were automatically as signed to the same treatment group to avoid hav ing more than one type of product in the home. If the family of a participant had a private water supply, the drinking water was analyzed to de
termine that the fluoride level was within the de sired range of 0.6 to 0.8 ppm fluoride. The children in group A received 0.5 mg fluoride (as sodium fluoride) with vitamins* up to 3 years of age; thereafter, the fluoride content of the vitamins was increased to 1.0 mg. Those in group B received only the vitamins* throughout the study period. Children in group C received a vitamin*-fluoride combination containing 0.5 mg fluoride (as sodium fluoride) throughout the study period. All children received a liquid product to about age 3 and a chewable tablet thereafter. As the children aged, the vitamin compositions were changed according to accepted pediatric vitamin therapy. Table 1 summarizes the treatment group regi mens. All products were indistinguishable in terms of taste, smell, and color and were packaged in coded containers. Instructions for daily use were on the label. The drops were to be placed on the tongue and swallowed; the tablets were to be chewed and then swallowed. Early in the study the products were mailed to each family. Later, a six-months’ supply of the product was dispensed at the time of each dental examination. If a child missed an examination period, the appropriate product was mailed to the home so that usage would not be interrupted. No attempt was made to monitor product use. Dental examinations were begun when the children were 30 to 36 months of age. Examina tions were repeated approximately every six months throughout the study, according to the procedure described previously.9 Sharp explorers and plane-surface mouth mirrors were used for the clinical examinations. The mouth was illumi nated with a portable examining light. Carious lesions were diagnosed on the basis of both visual and tactile evidence of enamel changes. The
THE AUTHORS
Dr. Hennon is with the department of pedodontics, In diana University School of Dentistry. Drs. Stookey and Beiswanger are with the Oral Health Research Institute, Indiana University School of Dentistry, 410 Beauty Ave, In dianapolis, 46202. Address requests for reprints to Dr. Stookey. HENNON
966 ■ JADA, Vol. 95, November 1977
STOOKEY
BEISWANGER
T a b le 1 ■ C h ro n o lo g ic a l ag e o f particip ants.
Group A B
c
< 1 yr Vitamins* + 0.5 mg F Vitamins* + Only Vitamins* + 0.5 mg F
1-3 yr Vitaminst + 0.5 mg F Vitaminst Only Vitaminst + 0.5 mg F
> 3 yr Vitaminst + 1.0 mg F Vitaminst Only Vitaminst + 0.5 mg F
*Tri-Vi-Sol or Tri-Vi-Flor Drops. fPoly-Vi-Sol or Poly-Vi-Flor Drops. tDeca-Vi-Sol or Deca-Vi-Flor Chewable Tablets.
caries examiner (D.K.H.) had previously partici pated in several clinical studies2,3,910 and had demonstrated an ability to detect significant inter group differences in caries prevalence with sup plemental fluoride regimens. The teeth were not dried with air before the examination. This procedure was omitted to avoid frightening the children with the noise from a portable air compressor. This was especially important for the initial examinations, since about 75% of the participants had never been to a den tist. A dental technician took posterior bitewing and maxillary and mandibular anterior occlusal radiographs of each child. Initially, it was not possible to obtain radiographs of diagnostic qual ity for some of the children because they were noncommunicative or uncooperative. Later in the study, suitable radiographs were obtained on every child. After about seven years, the study was termi nated with a fluorosis examination of the perma nent teeth. (No attempt was made to differentiate between idiopathic enamel opacities and dental fluorosis; all such clinical defects were identified and considered as dental fluorosis in this study.) Enamel fluorosis was classified according to Dean’s scale11 in which the absence of fluorosis was given a score of 0; questionable, 0.5; very mild, 1.0; mild, 2.0; moderate, 3.0; and severe, 4.0. The individual scores from the fluorosis examination were used to calculate the fluorosis index as described by Dean.11 The fluorosis examiner (D.K.H.) had only limited prior experi ence in performing fluorosis examinations; this experience consisted of examinations of patients in clinical practice and patients at the School of Dentistry. Dental caries data were tabulated two ways: according to the length of product use at each examination, and by age of the participant at each examination. Only caries scores for children who had both a clinical and radiographic examination were tabulated. Caries prevalence in primary and permanent teeth was reported as def and DMF teeth and surfaces, respectively. The results were not analyzed longitudinally
since not all children were present for each examination. Therefore, each examination period represented a cross-sectional sampling. Statisti cal evaluations for the dental caries data were performed by using the two-tailed Student’s t test. Differences at P<0.05 were considered signifi cant.
Results Table 2 shows values for def teeth and surfaces as a function of the length of product use. While positive differences in caries prevalence were evident in groups A and C as early as 24 months following product use initiation, these differences were not statistically significant until after 48 months of product use. At this time, group A had 37% and 38% fewer def teeth and surfaces, re spectively, than the participants in the control group B, whereas the children in group C had similar differences of 37% and 36%. Similarly, after 54 months of product use, the children in group A had 30% and 36% fewer def teeth and surfaces than the control group. The children in group C showed 27% and 23% fewer def teeth and surfaces than the participants in the control group, although the latter difference was not statistically significant. Numerically greater cariostatic benefits were observed after 60 months of product use. At this time, the children in group A had 42% and 47% fewer def teeth and surfaces, whereas the children in group C had slightly smaller differences of 32% and 37% compared with the control group. After 66, 72, and 78 months of product use, numerically positive differences in def teeth and surfaces were observed in most instances in the children receiv ing supplemental fluoride; some of these differ ences approached statistical significance but none were significant. Table 3 presents the caries prevalence data for the primary teeth according to the age of the chil dren at each examination period. Positive differ ences were observed at all age periods although many of the differences were not statistically sig nificant. At 36 months of age, the children in
Hennon— Stookey— Beiswanger: FLUORIDE-VITAMIN SUPPLEMENTS ■ 967
Table 2 ■ Caries prevalence in p rim a ry teeth o f c h ild re n a c c o rd in g to length o f tim e ta kin g p ro d u ct. Months of use 24
Group* (mg F dosage)
No. of participants
(0.5/1.0) (0.5)
33 36 37
% difference
def surfaces
% difference
0.48±0.19 0 .19 ± 0.10 0.62±0.24
22.6
0.48±0.20 0.19 ±0.10 0.70±0.28
31.4 72.9
55 40 44
0.89±0.20 0.53±0.19 1.16±0.33_
23.3 54.3
1.00±0.24 0.53±0.19 1.55±0.51_
35.5 65.8
48 43 47
1 67±0.23 1.44±0.31 2.15±0.43_
22.3 33.0
1.98±0.35 1.63±0.39 2.53±0.61J
2 1.7 35.6
52 52 52
2.17±0 .34 1.98±0.37 3.23±0.49_
32.8 38.7
2.73±0.49" 2.69±0.60 3.88±0.62
29.6 30.7
49 47 41
2.92 ±0.381 2.89±0.4lJ 4.61 ±0.59
36.7 37.3
3.59±0. 3.74±0. 5.83±0.
38.3 35.8
50 53 41
3.52±0.: 0.39] 3.68±0.' 0.43J 5.05 ±0.50 0.50
30.3 27.1
4.26±0. 5 .11 ±0
36.0 23.3
(0.5/1.0) (0.5)
( 0. 0 )
44 47 41
3.48±0.< 0.471 4.09±0.' 0.44J 6 .02±0.6 1'
42.2 32.1
4.59±0.711 5.43±0.75j
47.1 37.4
(0.5/1.0) (0.5)
31 37
23.4 19.2
5.87±0.90' 6.62±0.99
28.2 19.1
22
4.35±0.55 4.59±0.53 5.68±0.68
26 27 21
4.58±0.59 5.04±0.58 5.14±0.66J
10.9 1.9
5.88±0.87 7 .3 3 ± 1.1 1 7 .10 ± 1.0 3
17.2 (3.1)
( 0 . 0)
30 (0.5/1.0) (0.5) ( 0 .0 )
36 (0.5/1.0) (0.5) ( 0 .0 )
42
(0.5/1.0) (0.5) (0 .0 )
48 (0.5/1.0) (0.5) (0 .0 )
54 (0.5/1.0) (0.5) (0 .0 )
60
66 ( 0 . 0)
72
78
A (0.5/1.0) C (0.5) B (0.0)
def teethf
69.4
6 .6 6 ± 0
8.68±1.11
8.18±1.17
14 A (0.5/1.0) 4.50±0.91 16.7 6.93±1.69 21.6 27.2 C (0.5) 15 3.93±0.75 5.07±1.20 42.4 B (0.0) 10 5.40±0.91 8.80±1.76 * Group A, 0.5 mg F daily to age 3 and 1.0 mg F dally thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout, t Standard error of the mean. i Values within brackets do not differ significantly (P<0.05).
group C had 75% and 82% fewer def teeth and surfaces than the children in the control group. However, no other significant differences oc curred until 54 months of age. At this time, the children in group A experienced 41% and 43% fewer carious teeth and surfaces. The most consistent differences in caries preva lence occurred at 60 and 66 months of age. At 60 months, the children in group A had 32% and 35% fewer def teeth and surfaces. Children in group C showed differences in def teeth and surfaces of 44% and 43%. Similarly, at 66 months of age, the children in group A had 38% and 45% fewer def teeth and surfaces, whereas those in group C had 34% and 40% fewer def teeth and surfaces. Throughout the remaining periods (72, 78, and 84 months) the numerical differences in caries preva lence were not statistically significant. Tables 4 and 5 present the clinical data on fluorosis observed in the permanent teeth. The mean age of the children with permanent teeth ranged from 6.7 to 6.9 years. There were no signif icant differences in ages or in length of product 968 ■ JADA, Vol. 95, November 1977
use between any of the groups. The average length of time that the children consumed the product ranged from 80.4 to 82.1 months. Partici pants in group A had an average of 8.1 erupted permanent teeth at the time of the fluorosis examination, whereas comparable averages of 7.4 and 7.9 were recorded for children in groups B and C. N o clinically significant amounts of fluorosis were noted in any group. Children in group A had an index of fluorosis of 0.250. The fluorosis index for the children in group C was 0.188 and was 0.033 for the control group. The findings for both of the groups of children receiving supplemental fluoride (groups A and C) were significantly dif ferent from that of the children in the control group B. However, in no instance did the ob served values approach the value of 0.4 cited by Dean11 as being the lowest limit of concern. N o moderate or severe degrees of fluorosis were observed in any of the children. The cate gory, “questionable,” was noted most fre quently; eight of the children were in the 1.0 mg
T a b le 3 ■ C aries p revalence in p rim a ry teeth o f ch ild re n a cco rd in g to age. Months of age 30
36
42
48
54
60
66
72
78
84
Group* (mg F dosage)
No. of participants
def teethf
% difference
def surfaces
% difference
34.5 69.0
0.38±0.16' 0 .18± 0 .14 0.65±0.24
41.5 72.3
A (0.5/1.0) C (0.5) B (0.0)
42 39 40
0.38±0.16~ 0 .18 ± 0 .14 0.58±0.21_
A (0.5/1.0) C (0.5) B (0.0)
49 39 49
1.18 ± 0 .2 3 -i 0.46±0.14 1.86±0.46j
36.6 75.3
1 ,35±0.28~h 0.46±0.14 2.49±0.69~
45.8 81.5
A (0.5/1.0) C (0.5) B (0.0)
49 41 40
1.53±0.30 1.12 ± 0 .3 2 2.18±0.45
29.8 48.6
1.88±0.43 1.27±0.39 2.53±0.60_
25.7 49.8
A (0.5/1.0) C (0.5) B (0.0)
45 50 51
2.18 ±0.33 2.02±0.39 2.86±0.45
23.8 29.4
2.78±0.49" 2.66±0.59 3.16±0.52_
12.0 15.8
A (0.5/1.0) C (0.5) B (0.0)
54 50 47
2.67 ±0.37'I 3.18±0.43 4.55±0.56
4 1.3 30.1
3.35±0.53~ I 4.28±0.74 1 5.85±0.85
42.7 26.8 34.8 42.6
t
H
J
F
J
A (0.5/1.0) C (0.5) B (0.0)
49 48 42
3.53±0.43 2.90±0.43 5.19 ±0.51
32.0 44.1
4.41 ±0.62' 3.88±0.67 6.76±0.80
A (0.5/1.0) C (0.5) B (0.0)
47 49 37
3.77±0.46l 3.96±0.44j 6.03±0.61
37.5 34.3
4.89±0.69 5.31 ±0.75 8.86 ± 1.16"
44.8 40.1
A (0.5/1.0) C (0.5) B (0.0)
35 38 24
3.97±0.50 4.66±0.48 5.29±0.62_
25.0 11.9
5 .11 ±0.74” 6.32±0.81 7 .6 3 ± 1.10
33.0 17.2
A (0.5/1.0) C (0.5) B (0.0)
19 29 14
4.47±0.58 4.97±0.51 5.21 ±0.79.
14.2 4.6
5.89±1.04 7 .0 7 ± 1.05 7.79 ±1.41
24.4 9.2
22.2 13 4.85±0.78 16.7 7.0 0± 1.51 A (0.5/1.0) 17 4.53±0.95 6.24±1.59 30.7 C (0.5) 22.2 9.00±1.47 11 5.82±0.81 B (0.0) * Group A, 0.5 mg F daily to age 3 and 1.0 mg F daily thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout, t Standard error of the mean. i Values within brackets do not differ significantly (P<0.05).
fluoride group and ten were in the 0.5 mg fluoride group. The fluorosis in one child in group A (1.0 mg fluoride) was classified as mild. As permanent teeth erupted (that is, after about 54 months of product use), they were examined for caries prevalence. The findings were also tabulated according to the child’s age and the length of time the product was consumed. Since no significant differences in DMF teeth or sur faces were observed between any of the experi mental groups at any of the examination periods, these data are not reported.
Discussion The consistent benefits in terms of caries preva lence in the primary teeth observed at nearly all examination periods indicate a strong trend to ward a beneficial effect associated with the inges tion of supplemental fluoride. However, not all of these intergroup differences were statistically significant, probably because of the small number of participants per group and the cross-sectional
sampling procedure. A similar trend was reported in our previous study2,9 in which significant re ductions were not observed until after about three years of product use. Another factor that contributed to make the intergroup differences not significant for the younger age groups was the lower absolute values for caries prevalence as a result of the partially fluoridated water. For example, at 30 months of age, the children in control group B had an aver age of 0.65 def surfaces. Children of a comparable age in a nonfluoride area examined by the same investigator (D.K.H.) had an average of 1.50 def surfaces.10 Thus, any significant differences be tween the control and treatment groups in the present study represent a benefit of the fluoride supplements in addition to that obtained from the suboptimally fluoridated water supply. There was no consistent superiority of the 1.0-mg fluoride supplemental regimen (after three years of age) over the 0.5-mg dosage level when used in the suboptimal fluoride area. This finding agrees with that of Dean and co-workers12 who showed that the benefits from communal fluorida-
Hennon— Stookey— Beiswanger: FLUORIDE-VITAMIN SUPPLEMENTS ■ 969
Table 4 ■ R esults o f flu o ro sis ex a m in a tio n . Group* (mg F dosage)
No. of participants
Mean age (months)
Mean months on product
Mean no. permanent teeth
32 32 30
6.9±O .I2lt 6 .7±0 .13 6 .8 ± 0 .11J
82.1 ±0.73" 80.4±0.90 80.6±0.85J
8.1 ±0.55" 7.9±0.56 7.4±0.49j
A (0.5/1.0) C (0.5) B (0.0)
'Group A, 0.5 mg F daily to age 3 and 1.0 mg F daily thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout. fValues within brackets do not duffer significantly (P<0.05).
Table 5 ■ D is trib u tio n o f flu o ro s is severity.* Groupt (mg F dosage) A (0.5/1.0) C (0.5) B (0.0)
No. of participants
Normal
Questionable
Very mild
Mild
Index
32 32 30
21 21 28
8 10 2
2 1 0
1 0 0
0.2501$ 0 .188J 0,033
*No patients having “ moderate” or “ severe” fluorosis were observed. tGroup A, 0.5 mg F daily to age 3 and 1.0 mg F daily thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout. ^Values within brackets do not differ significantly (P < 0.05).
tion became greater as the water fluoride concen trations increased up to about 1.2 ppm; water fluoride levels above 1.2 ppm resulted in little or no additional benefits. During the latter part of the study, there were too few children to obtain statistical and meaning ful comparisons. The problem of maintaining adequate numbers in long-term studies of this type has been discussed in other papers.313 Fluoride supplements are not as universally effec tive as fluoridated water in controlling dental caries because many parents lack motivation to ensure that their children ingest the supplements regularly.14,15 The trend in reductions in dental caries in this study lends support to the findings in our previous studies2,3,9 that showed fluoride-vitamin prepara tions to be effective in controlling caries. Also, the results are in agreement with those of other investigators who showed a significant anticariogenic effect from fluoride supplements.4'6 That no anticariogenic effect of the supple ments was observed in permanent teeth in this particular study may be a result of the low inci dence of caries in anterior permanent teeth at this age; the small number of permanent teeth examined; the decreased benefit of fluoride against pit and fissure caries versus smooth sur face caries; and the anticariogenic benefit of the suboptimally fluoridated water, which may have partially masked the effects of fluoride supple mentation. The fluorosis indexes computed from the fluorosis examinations show that none of the sub jects in any of the treatment groups had unaccept able amounts of fluorosis. Dean11 said that a 970 ■ JADA, Vol. 95, November 1977
fluorosis index of 0.4 or less is considered to be of no concern. An index of 0.6 or more is termed ‘‘unacceptable” and this level begins to constitute a public health problem that needs further atten tion. In group A (0.5 mg fluoride to age 3; 1.0 mg thereafter), the children had a fluorosis index of 0.250. Those in group C (0.5 mg fluoride through out) had an index of 0.188. Both of these values are well below Dean’s level of concern (0.4) and are slightly above the values calculated from the data of Schlesinger and A st’s KingstonNewburgh study,16 a controlled water fluorida tion trial. They are also less than the value of 0.88 reported by Aasenden and Peebles.4
Summary A clinical dental caries study was conducted for more than seven years beginning with infants 1 to 14 months of age residing in suboptimum fluoride areas (0.6 to 0.8 ppm fluoride). Two investiga tional groups received 0.5 mg fluoride with vita mins up to three years of age; one of these groups continued to receive the same dosage, and the dosage for the other group was increased to 1.0 mg fluoride per day. The control group received only vitamins. Caries prevalence was determined semiannually after the children reached 30 to 36 months of age and the prevalence and degree of dental fluorosis was determined at the conclusion of the study. The results of the dental caries examinations tend to indicate that both supplemental fluoride regimens were effective in providing added an-
ticariogenic benefits in primary teeth beyond that received from the suboptimally fluoridated drink ing water. In addition, the fluorosis indexes ob tained in this study indicate that additional fluoride, up to 1.0 mg per day, resulted in a statis tically significant increase in the prevalence of fluorosis but did not cause cosmetically unac ceptable fluorosis. On the basis of this investiga tion, we suggest that levels of fluoride supple mentation can be safely ingested by children re siding in areas where the water supply contains 0.6 to 0.8 ppm fluoride.
Supported in part by a grant from Mead Johnson Research Cen ter, Evansville, Ind. 'Mead Johnson Laboratories, Evansville, Ind 47721.
1. Estimated Fluoridation Total (Dec 3 1,19 7 4 ). ADA Fluor Report vol 12, No. 2, 1974. 2. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C . The clinical anticariogenic effectiveness of supplementary fluoride-vitamin preparations. Results at the end of five and a half years. J Phar and Ther in Dent 1 :1 Oct 1970. 3. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C. Prophylaxis of dental caries: relative effectiveness of chewable fluoride prepara tions with and without added vitamins. J Pediatrics 8 0 :10 18 June 1974. 4. Aasenden, R., and Peebles, T.C. Effects of fluoride supple
mentation from birth on deciduous and permanent teeth. Arch Oral Biol 19 :32 1 April 1974. 5. Driscoll, W.S.; Heifetz, S.B.; and Korts, D.C. Effect of acidu lated phosphate-fluoride chewable tablets on dental caries in school children: results after 30 months. JADA 8 9 :115 July 1974. 6. Margolis, F.J., and others. Fluoride. Ten-year prospective study of deciduous and permanent dentition. Am J Dis Child 129:794 July 1975. 7. Galagan, D.J., and Vermillion, J.R . Determining optimum fluoride concentrations. Public Health Rep 72:491, 1957. 8. Accepted Dental Therapeutics, ed 36. Chicago, American Dental Association, 1975, p 292. 9. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C . The clinical anticariogenic effectiveness of supplementary fluoride-vitamin preparations. Results at the end of three years. J Dent Child 33:3 Ja n 1966. 10. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C . Prevalence and distribution of dental caries in preschool children. JADA 79:1405 Dec 1969. 1 1 . Dean, H.T. The investigation of physiological effects by the epidemiological method. In Moulton, F.R., ed. Fluorine and Dental Health. Washington, D.C., AAAS publ no. 19, 1942, p 23. 12. Dean, H.T.; Arnold, F.A., Jr.; and Elvove, E. Domestic water and dental caries. V. Additional studies of the relation of fluoride domestic waters to dental caries experience in 4,425 white chil dren, aged 12 to 14 years, of 13 cities in 4 states. Public Health Rep 5 7 :1 1 5 5 Aug 1942. 13 . Arnold, F.A.; McClure, F.J.; and White, C.L. Sodium fluoride tablets for children. Dent Prog 1 :8 Jan 1960. 14. Richardson, A.S. Parental participation in the administration of fluoride supplements. Can J Public Health 58:508 Nov 1967. 15. Fanning, E.A., and others. South Australian kindergarten children: fluoride tablet supplements and dental caries. Austral Dent J 20:7 Feb 1975. 16. Schlesinger, E.F.,andAst, D.B. Use of fluoride compounds in the prevention of dental caries. Adv Pediatrics 9 :19 1, 1957.
H e i* s * i» 4 to o k e y — Beiswanger: FLUORIDE-VITAMIN SUPPLEMENTS ■ 971
Fluoride-vitamin supplements: effects on dental caries and fluorosis when used in areas with suboptimum fluoride in the water supply
David K. Hennon, DDS, MSD George K. Stookey, MSD, PhD Bradley B. Beiswanger, DDS, India n a p o lis
Drinking water containing an optimum amount of fluoride has been recognized as an effective method to decrease the incidence of dental caries. Fluoridation of municipal water supplies is often acknowledged as a basic public health measure since it is highly effective, safe, and economical and since persons acquire the benefits without conscious effort. In 1974, about half the US popu lation, or more than 100 million persons, were served by water supplies containing an optimum concentration of fluoride either naturally or me chanically added.1 Fluoride supplements, alone or in vitamin combinations, are effective in decreasing the inci dence of dental caries in children living in areas with no fluoride in the water supply.2-6 However, no studies have been reported that evaluated the anticariogenic benefits of fluoride supplements used in areas containing suboptimum amounts of fluoride in the water (that is, 0.6 to 0.8 ppm com pared with the optimum value of 1.0 ppm for In
diana). For a discussion of how optimum fluoride levels in drinking water are established for differ ent geographic areas, the reader is referred to the work of Galagan and Vermillion.7 It was questioned whether a fluoride supple ment would give added protection against dental caries in these areas and whether the additional fluoride would cause any significant increase in dental fluorosis. The answer to these questions are important since the A D A Council on Dental Therapeutics8 recommends that the supplemental fluoride dosage be decreased as the level of fluoride in drinking water increases from 0.0 to 0.7 ppm. If extra fluoride could be given in a fixed, convenient dosage form in all areas where water contained 0.7 ppm fluoride or less, the problem of calculating and titrating individual fluoride dos ages would be eliminated. Thus, physicians and dentists may be more likely to prescribe fluoride supplements for infants and children who could benefit from the additional fluoride. JADA, Vol. 95, November 1977 ■ 965
M e th o d s a n d m a te ria ls
A total of 456 infants, 1 to 14 months of age, living in eight different Indiana communities having 0.6 to 0.8 ppm fluoride in their water supplies, were scheduled and examined initially for this project. In Indiana, the water fluoride content of all com munities is surveyed periodically by the Indiana State Board of Health. These data (not published) were used to select the communities for inclusion in this study. A list of children in the desired age range was obtained by screening birth records for each of the cities through the cooperation of the Indiana State Board of Health. A letter explaining the purpose and procedures of this program and a permission form were sent to the parents. Only those children for whom signed parental consent forms were returned were enrolled in the study. The parents of the participants could withdraw them from the program at any time. Physicians and dentists in each of these com munities received the same information letter that was sent to the parents. Whenever possible, the program was also explained to physicians and dentists at meetings of their professional societies. Special meetings to explain the program were held with the administrative officials in each city; the newspapers in each area were also in formed. Each child was assigned to one of three study groups by systematic allocation after stratifica tion by sex and age. Neither the clinical examiner (D .K .H .) for dental caries and fluorosis, nor the patients had knowledge of group assignments or product codes. Siblings were automatically as signed to the same treatment group to avoid hav ing more than one type of product in the home. If the family of a participant had a private water supply, the drinking water was analyzed to de
termine that the fluoride level was within the de sired range of 0.6 to 0.8 ppm fluoride. The children in group A received 0.5 mg fluoride (as sodium fluoride) with vitamins* up to 3 years of age; thereafter, the fluoride content of the vitamins was increased to 1.0 mg. Those in group B received only the vitamins* throughout the study period. Children in group C received a vitamin*-fluoride combination containing 0.5 mg fluoride (as sodium fluoride) throughout the study period. All children received a liquid product to about age 3 and a chewable tablet thereafter. As the children aged, the vitamin compositions were changed according to accepted pediatric vitamin therapy. Table 1 summarizes the treatment group regi mens. All products were indistinguishable in terms of taste, smell, and color and were packaged in coded containers. Instructions for daily use were on the label. The drops were to be placed on the tongue and swallowed; the tablets were to be chewed and then swallowed. Early in the study the products were mailed to each family. Later, a six-months’ supply of the product was dispensed at the time of each dental examination. If a child missed an examination period, the appropriate product was mailed to the home so that usage would not be interrupted. No attempt was made to monitor product use. Dental examinations were begun when the children were 30 to 36 months of age. Examina tions were repeated approximately every six months throughout the study, according to the procedure described previously.9 Sharp explorers and plane-surface mouth mirrors were used for the clinical examinations. The mouth was illumi nated with a portable examining light. Carious lesions were diagnosed on the basis of both visual and tactile evidence of enamel changes. The
THE AUTHORS
Dr. Hennon is with the department of pedodontics, In diana University School of Dentistry. Drs. Stookey and Beiswanger are with the Oral Health Research Institute, Indiana University School of Dentistry, 410 Beauty Ave, In dianapolis, 46202. Address requests for reprints to Dr. Stookey. HENNON
966 ■ JADA, Vol. 95, November 1977
STOOKEY
BEISWANGER
T a b le 1 ■ C h ro n o lo g ic a l ag e o f particip ants.
Group A B
c
< 1 yr Vitamins* + 0.5 mg F Vitamins* + Only Vitamins* + 0.5 mg F
1-3 yr Vitaminst + 0.5 mg F Vitaminst Only Vitaminst + 0.5 mg F
> 3 yr Vitaminst + 1.0 mg F Vitaminst Only Vitaminst + 0.5 mg F
*Tri-Vi-Sol or Tri-Vi-Flor Drops. fPoly-Vi-Sol or Poly-Vi-Flor Drops. tDeca-Vi-Sol or Deca-Vi-Flor Chewable Tablets.
caries examiner (D.K.H.) had previously partici pated in several clinical studies2,3,910 and had demonstrated an ability to detect significant inter group differences in caries prevalence with sup plemental fluoride regimens. The teeth were not dried with air before the examination. This procedure was omitted to avoid frightening the children with the noise from a portable air compressor. This was especially important for the initial examinations, since about 75% of the participants had never been to a den tist. A dental technician took posterior bitewing and maxillary and mandibular anterior occlusal radiographs of each child. Initially, it was not possible to obtain radiographs of diagnostic qual ity for some of the children because they were noncommunicative or uncooperative. Later in the study, suitable radiographs were obtained on every child. After about seven years, the study was termi nated with a fluorosis examination of the perma nent teeth. (No attempt was made to differentiate between idiopathic enamel opacities and dental fluorosis; all such clinical defects were identified and considered as dental fluorosis in this study.) Enamel fluorosis was classified according to Dean’s scale11 in which the absence of fluorosis was given a score of 0; questionable, 0.5; very mild, 1.0; mild, 2.0; moderate, 3.0; and severe, 4.0. The individual scores from the fluorosis examination were used to calculate the fluorosis index as described by Dean.11 The fluorosis examiner (D.K.H.) had only limited prior experi ence in performing fluorosis examinations; this experience consisted of examinations of patients in clinical practice and patients at the School of Dentistry. Dental caries data were tabulated two ways: according to the length of product use at each examination, and by age of the participant at each examination. Only caries scores for children who had both a clinical and radiographic examination were tabulated. Caries prevalence in primary and permanent teeth was reported as def and DMF teeth and surfaces, respectively. The results were not analyzed longitudinally
since not all children were present for each examination. Therefore, each examination period represented a cross-sectional sampling. Statisti cal evaluations for the dental caries data were performed by using the two-tailed Student’s t test. Differences at P<0.05 were considered signifi cant.
Results Table 2 shows values for def teeth and surfaces as a function of the length of product use. While positive differences in caries prevalence were evident in groups A and C as early as 24 months following product use initiation, these differences were not statistically significant until after 48 months of product use. At this time, group A had 37% and 38% fewer def teeth and surfaces, re spectively, than the participants in the control group B, whereas the children in group C had similar differences of 37% and 36%. Similarly, after 54 months of product use, the children in group A had 30% and 36% fewer def teeth and surfaces than the control group. The children in group C showed 27% and 23% fewer def teeth and surfaces than the participants in the control group, although the latter difference was not statistically significant. Numerically greater cariostatic benefits were observed after 60 months of product use. At this time, the children in group A had 42% and 47% fewer def teeth and surfaces, whereas the children in group C had slightly smaller differences of 32% and 37% compared with the control group. After 66, 72, and 78 months of product use, numerically positive differences in def teeth and surfaces were observed in most instances in the children receiv ing supplemental fluoride; some of these differ ences approached statistical significance but none were significant. Table 3 presents the caries prevalence data for the primary teeth according to the age of the chil dren at each examination period. Positive differ ences were observed at all age periods although many of the differences were not statistically sig nificant. At 36 months of age, the children in
Hennon— Stookey— Beiswanger: FLUORIDE-VITAMIN SUPPLEMENTS ■ 967
Table 2 ■ Caries prevalence in p rim a ry teeth o f c h ild re n a c c o rd in g to length o f tim e ta kin g p ro d u ct. Months of use 24
Group* (mg F dosage)
No. of participants
(0.5/1.0) (0.5)
33 36 37
% difference
def surfaces
% difference
0.48±0.19 0 .19 ± 0.10 0.62±0.24
22.6
0.48±0.20 0.19 ±0.10 0.70±0.28
31.4 72.9
55 40 44
0.89±0.20 0.53±0.19 1.16±0.33_
23.3 54.3
1.00±0.24 0.53±0.19 1.55±0.51_
35.5 65.8
48 43 47
1 67±0.23 1.44±0.31 2.15±0.43_
22.3 33.0
1.98±0.35 1.63±0.39 2.53±0.61J
2 1.7 35.6
52 52 52
2.17±0 .34 1.98±0.37 3.23±0.49_
32.8 38.7
2.73±0.49" 2.69±0.60 3.88±0.62
29.6 30.7
49 47 41
2.92 ±0.381 2.89±0.4lJ 4.61 ±0.59
36.7 37.3
3.59±0. 3.74±0. 5.83±0.
38.3 35.8
50 53 41
3.52±0.: 0.39] 3.68±0.' 0.43J 5.05 ±0.50 0.50
30.3 27.1
4.26±0. 5 .11 ±0
36.0 23.3
(0.5/1.0) (0.5)
( 0. 0 )
44 47 41
3.48±0.< 0.471 4.09±0.' 0.44J 6 .02±0.6 1'
42.2 32.1
4.59±0.711 5.43±0.75j
47.1 37.4
(0.5/1.0) (0.5)
31 37
23.4 19.2
5.87±0.90' 6.62±0.99
28.2 19.1
22
4.35±0.55 4.59±0.53 5.68±0.68
26 27 21
4.58±0.59 5.04±0.58 5.14±0.66J
10.9 1.9
5.88±0.87 7 .3 3 ± 1.1 1 7 .10 ± 1.0 3
17.2 (3.1)
( 0 . 0)
30 (0.5/1.0) (0.5) ( 0 .0 )
36 (0.5/1.0) (0.5) ( 0 .0 )
42
(0.5/1.0) (0.5) (0 .0 )
48 (0.5/1.0) (0.5) (0 .0 )
54 (0.5/1.0) (0.5) (0 .0 )
60
66 ( 0 . 0)
72
78
A (0.5/1.0) C (0.5) B (0.0)
def teethf
69.4
6 .6 6 ± 0
8.68±1.11
8.18±1.17
14 A (0.5/1.0) 4.50±0.91 16.7 6.93±1.69 21.6 27.2 C (0.5) 15 3.93±0.75 5.07±1.20 42.4 B (0.0) 10 5.40±0.91 8.80±1.76 * Group A, 0.5 mg F daily to age 3 and 1.0 mg F dally thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout, t Standard error of the mean. i Values within brackets do not differ significantly (P<0.05).
group C had 75% and 82% fewer def teeth and surfaces than the children in the control group. However, no other significant differences oc curred until 54 months of age. At this time, the children in group A experienced 41% and 43% fewer carious teeth and surfaces. The most consistent differences in caries preva lence occurred at 60 and 66 months of age. At 60 months, the children in group A had 32% and 35% fewer def teeth and surfaces. Children in group C showed differences in def teeth and surfaces of 44% and 43%. Similarly, at 66 months of age, the children in group A had 38% and 45% fewer def teeth and surfaces, whereas those in group C had 34% and 40% fewer def teeth and surfaces. Throughout the remaining periods (72, 78, and 84 months) the numerical differences in caries preva lence were not statistically significant. Tables 4 and 5 present the clinical data on fluorosis observed in the permanent teeth. The mean age of the children with permanent teeth ranged from 6.7 to 6.9 years. There were no signif icant differences in ages or in length of product 968 ■ JADA, Vol. 95, November 1977
use between any of the groups. The average length of time that the children consumed the product ranged from 80.4 to 82.1 months. Partici pants in group A had an average of 8.1 erupted permanent teeth at the time of the fluorosis examination, whereas comparable averages of 7.4 and 7.9 were recorded for children in groups B and C. N o clinically significant amounts of fluorosis were noted in any group. Children in group A had an index of fluorosis of 0.250. The fluorosis index for the children in group C was 0.188 and was 0.033 for the control group. The findings for both of the groups of children receiving supplemental fluoride (groups A and C) were significantly dif ferent from that of the children in the control group B. However, in no instance did the ob served values approach the value of 0.4 cited by Dean11 as being the lowest limit of concern. N o moderate or severe degrees of fluorosis were observed in any of the children. The cate gory, “questionable,” was noted most fre quently; eight of the children were in the 1.0 mg
T a b le 3 ■ C aries p revalence in p rim a ry teeth o f ch ild re n a cco rd in g to age. Months of age 30
36
42
48
54
60
66
72
78
84
Group* (mg F dosage)
No. of participants
def teethf
% difference
def surfaces
% difference
34.5 69.0
0.38±0.16' 0 .18± 0 .14 0.65±0.24
41.5 72.3
A (0.5/1.0) C (0.5) B (0.0)
42 39 40
0.38±0.16~ 0 .18 ± 0 .14 0.58±0.21_
A (0.5/1.0) C (0.5) B (0.0)
49 39 49
1.18 ± 0 .2 3 -i 0.46±0.14 1.86±0.46j
36.6 75.3
1 ,35±0.28~h 0.46±0.14 2.49±0.69~
45.8 81.5
A (0.5/1.0) C (0.5) B (0.0)
49 41 40
1.53±0.30 1.12 ± 0 .3 2 2.18±0.45
29.8 48.6
1.88±0.43 1.27±0.39 2.53±0.60_
25.7 49.8
A (0.5/1.0) C (0.5) B (0.0)
45 50 51
2.18 ±0.33 2.02±0.39 2.86±0.45
23.8 29.4
2.78±0.49" 2.66±0.59 3.16±0.52_
12.0 15.8
A (0.5/1.0) C (0.5) B (0.0)
54 50 47
2.67 ±0.37'I 3.18±0.43 4.55±0.56
4 1.3 30.1
3.35±0.53~ I 4.28±0.74 1 5.85±0.85
42.7 26.8 34.8 42.6
t
H
J
F
J
A (0.5/1.0) C (0.5) B (0.0)
49 48 42
3.53±0.43 2.90±0.43 5.19 ±0.51
32.0 44.1
4.41 ±0.62' 3.88±0.67 6.76±0.80
A (0.5/1.0) C (0.5) B (0.0)
47 49 37
3.77±0.46l 3.96±0.44j 6.03±0.61
37.5 34.3
4.89±0.69 5.31 ±0.75 8.86 ± 1.16"
44.8 40.1
A (0.5/1.0) C (0.5) B (0.0)
35 38 24
3.97±0.50 4.66±0.48 5.29±0.62_
25.0 11.9
5 .11 ±0.74” 6.32±0.81 7 .6 3 ± 1.10
33.0 17.2
A (0.5/1.0) C (0.5) B (0.0)
19 29 14
4.47±0.58 4.97±0.51 5.21 ±0.79.
14.2 4.6
5.89±1.04 7 .0 7 ± 1.05 7.79 ±1.41
24.4 9.2
22.2 13 4.85±0.78 16.7 7.0 0± 1.51 A (0.5/1.0) 17 4.53±0.95 6.24±1.59 30.7 C (0.5) 22.2 9.00±1.47 11 5.82±0.81 B (0.0) * Group A, 0.5 mg F daily to age 3 and 1.0 mg F daily thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout, t Standard error of the mean. i Values within brackets do not differ significantly (P<0.05).
fluoride group and ten were in the 0.5 mg fluoride group. The fluorosis in one child in group A (1.0 mg fluoride) was classified as mild. As permanent teeth erupted (that is, after about 54 months of product use), they were examined for caries prevalence. The findings were also tabulated according to the child’s age and the length of time the product was consumed. Since no significant differences in DMF teeth or sur faces were observed between any of the experi mental groups at any of the examination periods, these data are not reported.
Discussion The consistent benefits in terms of caries preva lence in the primary teeth observed at nearly all examination periods indicate a strong trend to ward a beneficial effect associated with the inges tion of supplemental fluoride. However, not all of these intergroup differences were statistically significant, probably because of the small number of participants per group and the cross-sectional
sampling procedure. A similar trend was reported in our previous study2,9 in which significant re ductions were not observed until after about three years of product use. Another factor that contributed to make the intergroup differences not significant for the younger age groups was the lower absolute values for caries prevalence as a result of the partially fluoridated water. For example, at 30 months of age, the children in control group B had an aver age of 0.65 def surfaces. Children of a comparable age in a nonfluoride area examined by the same investigator (D.K.H.) had an average of 1.50 def surfaces.10 Thus, any significant differences be tween the control and treatment groups in the present study represent a benefit of the fluoride supplements in addition to that obtained from the suboptimally fluoridated water supply. There was no consistent superiority of the 1.0-mg fluoride supplemental regimen (after three years of age) over the 0.5-mg dosage level when used in the suboptimal fluoride area. This finding agrees with that of Dean and co-workers12 who showed that the benefits from communal fluorida-
Hennon— Stookey— Beiswanger: FLUORIDE-VITAMIN SUPPLEMENTS ■ 969
Table 4 ■ R esults o f flu o ro sis ex a m in a tio n . Group* (mg F dosage)
No. of participants
Mean age (months)
Mean months on product
Mean no. permanent teeth
32 32 30
6.9±O .I2lt 6 .7±0 .13 6 .8 ± 0 .11J
82.1 ±0.73" 80.4±0.90 80.6±0.85J
8.1 ±0.55" 7.9±0.56 7.4±0.49j
A (0.5/1.0) C (0.5) B (0.0)
'Group A, 0.5 mg F daily to age 3 and 1.0 mg F daily thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout. fValues within brackets do not duffer significantly (P<0.05).
Table 5 ■ D is trib u tio n o f flu o ro s is severity.* Groupt (mg F dosage) A (0.5/1.0) C (0.5) B (0.0)
No. of participants
Normal
Questionable
Very mild
Mild
Index
32 32 30
21 21 28
8 10 2
2 1 0
1 0 0
0.2501$ 0 .188J 0,033
*No patients having “ moderate” or “ severe” fluorosis were observed. tGroup A, 0.5 mg F daily to age 3 and 1.0 mg F daily thereafter; group B, no fluoride, vitamins only; group C, 0.5 mg F daily throughout. ^Values within brackets do not differ significantly (P < 0.05).
tion became greater as the water fluoride concen trations increased up to about 1.2 ppm; water fluoride levels above 1.2 ppm resulted in little or no additional benefits. During the latter part of the study, there were too few children to obtain statistical and meaning ful comparisons. The problem of maintaining adequate numbers in long-term studies of this type has been discussed in other papers.313 Fluoride supplements are not as universally effec tive as fluoridated water in controlling dental caries because many parents lack motivation to ensure that their children ingest the supplements regularly.14,15 The trend in reductions in dental caries in this study lends support to the findings in our previous studies2,3,9 that showed fluoride-vitamin prepara tions to be effective in controlling caries. Also, the results are in agreement with those of other investigators who showed a significant anticariogenic effect from fluoride supplements.4'6 That no anticariogenic effect of the supple ments was observed in permanent teeth in this particular study may be a result of the low inci dence of caries in anterior permanent teeth at this age; the small number of permanent teeth examined; the decreased benefit of fluoride against pit and fissure caries versus smooth sur face caries; and the anticariogenic benefit of the suboptimally fluoridated water, which may have partially masked the effects of fluoride supple mentation. The fluorosis indexes computed from the fluorosis examinations show that none of the sub jects in any of the treatment groups had unaccept able amounts of fluorosis. Dean11 said that a 970 ■ JADA, Vol. 95, November 1977
fluorosis index of 0.4 or less is considered to be of no concern. An index of 0.6 or more is termed ‘‘unacceptable” and this level begins to constitute a public health problem that needs further atten tion. In group A (0.5 mg fluoride to age 3; 1.0 mg thereafter), the children had a fluorosis index of 0.250. Those in group C (0.5 mg fluoride through out) had an index of 0.188. Both of these values are well below Dean’s level of concern (0.4) and are slightly above the values calculated from the data of Schlesinger and A st’s KingstonNewburgh study,16 a controlled water fluorida tion trial. They are also less than the value of 0.88 reported by Aasenden and Peebles.4
Summary A clinical dental caries study was conducted for more than seven years beginning with infants 1 to 14 months of age residing in suboptimum fluoride areas (0.6 to 0.8 ppm fluoride). Two investiga tional groups received 0.5 mg fluoride with vita mins up to three years of age; one of these groups continued to receive the same dosage, and the dosage for the other group was increased to 1.0 mg fluoride per day. The control group received only vitamins. Caries prevalence was determined semiannually after the children reached 30 to 36 months of age and the prevalence and degree of dental fluorosis was determined at the conclusion of the study. The results of the dental caries examinations tend to indicate that both supplemental fluoride regimens were effective in providing added an-
ticariogenic benefits in primary teeth beyond that received from the suboptimally fluoridated drink ing water. In addition, the fluorosis indexes ob tained in this study indicate that additional fluoride, up to 1.0 mg per day, resulted in a statis tically significant increase in the prevalence of fluorosis but did not cause cosmetically unac ceptable fluorosis. On the basis of this investiga tion, we suggest that levels of fluoride supple mentation can be safely ingested by children re siding in areas where the water supply contains 0.6 to 0.8 ppm fluoride.
Supported in part by a grant from Mead Johnson Research Cen ter, Evansville, Ind. 'Mead Johnson Laboratories, Evansville, Ind 47721.
1. Estimated Fluoridation Total (Dec 3 1,19 7 4 ). ADA Fluor Report vol 12, No. 2, 1974. 2. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C . The clinical anticariogenic effectiveness of supplementary fluoride-vitamin preparations. Results at the end of five and a half years. J Phar and Ther in Dent 1 :1 Oct 1970. 3. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C. Prophylaxis of dental caries: relative effectiveness of chewable fluoride prepara tions with and without added vitamins. J Pediatrics 8 0 :10 18 June 1974. 4. Aasenden, R., and Peebles, T.C. Effects of fluoride supple
mentation from birth on deciduous and permanent teeth. Arch Oral Biol 19 :32 1 April 1974. 5. Driscoll, W.S.; Heifetz, S.B.; and Korts, D.C. Effect of acidu lated phosphate-fluoride chewable tablets on dental caries in school children: results after 30 months. JADA 8 9 :115 July 1974. 6. Margolis, F.J., and others. Fluoride. Ten-year prospective study of deciduous and permanent dentition. Am J Dis Child 129:794 July 1975. 7. Galagan, D.J., and Vermillion, J.R . Determining optimum fluoride concentrations. Public Health Rep 72:491, 1957. 8. Accepted Dental Therapeutics, ed 36. Chicago, American Dental Association, 1975, p 292. 9. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C . The clinical anticariogenic effectiveness of supplementary fluoride-vitamin preparations. Results at the end of three years. J Dent Child 33:3 Ja n 1966. 10. Hennon, D.K.; Stookey, G.K.; and Muhler, J.C . Prevalence and distribution of dental caries in preschool children. JADA 79:1405 Dec 1969. 1 1 . Dean, H.T. The investigation of physiological effects by the epidemiological method. In Moulton, F.R., ed. Fluorine and Dental Health. Washington, D.C., AAAS publ no. 19, 1942, p 23. 12. Dean, H.T.; Arnold, F.A., Jr.; and Elvove, E. Domestic water and dental caries. V. Additional studies of the relation of fluoride domestic waters to dental caries experience in 4,425 white chil dren, aged 12 to 14 years, of 13 cities in 4 states. Public Health Rep 5 7 :1 1 5 5 Aug 1942. 13 . Arnold, F.A.; McClure, F.J.; and White, C.L. Sodium fluoride tablets for children. Dent Prog 1 :8 Jan 1960. 14. Richardson, A.S. Parental participation in the administration of fluoride supplements. Can J Public Health 58:508 Nov 1967. 15. Fanning, E.A., and others. South Australian kindergarten children: fluoride tablet supplements and dental caries. Austral Dent J 20:7 Feb 1975. 16. Schlesinger, E.F.,andAst, D.B. Use of fluoride compounds in the prevention of dental caries. Adv Pediatrics 9 :19 1, 1957.
H e i* s * i» 4 to o k e y — Beiswanger: FLUORIDE-VITAMIN SUPPLEMENTS ■ 971