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Effect on dental caries in children in a nonfluoride area of combined use of three agents containing stannous fluoride: a prophylactic paste, a solution, and a dentifrice II. Results at the end of 24 and 36 months
Effect on dental caries in children in a nonfluoride area of combined use of three agents containing stannous fluoride: a prophylactic paste, à solution, and a dentifrice II. Results at the end of 24 and 36 months
David Bixler, DDS, PhD Joseph C. M uhler, DDS, PhD, Indianapolis
In a clinical study conducted during 3 years in a nonfluoride community, children were given treatm ent using a prophylactic paste containing stannous fluoride, topically applied stannous fluoride, and a stannous fluoridecalcium pyrophosphate dentifrice for home use. Findings show that the children receiving all three forms of therapy had the greatest reduction in dental caries. These results, which verify data found in a previous 1-year study, indicate that the most effective use of topical stannous fluoride therapy In a non fluoridated com m unity takes place when a combination of all three technics is used.
In a previous report,1 data were presented dem onstrating the clinical effectiveness of combining three topical technics of applying stannous fluoride for reducing the dental caries experience in chil dren residing in a nonfluoride area. These three 392
technics involved adding stannous fluoride to a compatible lava pumice prophylactic paste, stan nous fluoride applied in an aqueous solution after a dental prophylaxis, stannous fluoride as a con stituent of a dentifrice containing calcium pyro phosphate as the polishing agent. Results at the end of a year indicated that the combination of all three technics was the most effective way to use stannous fluoride in reducing dental caries. This paper reports data obtained in this study at the end of 2 and 3 years.
M ethods The clinical design and conduct of the study dur ing the second and third clinical years was the same as reported for the first year of the pro gram.1 Briefly, the experimental groups were as follows: group 1 received 8.9 per cent SnF2 lava pumice prophylactic paste, designated PF; group 2 received PF plus SnF2 dentifrice for home use, designated DF; group 3 received PF plus a topical application of an 8 per cent aqueous solution of SnF2, designated TF; group 4 received PF + DF + Tf ; group 5 served as the control and- received the appropriate placebo treatments. Groups 1 and 3 also received the placebo dentifrice. Two examiners were employed, each to ex amine a specific segment of each group through
T ab le 1
Balance in terms of initial D M FS and age for subjects completing 24 and 36 months in the study Examiner A
Group
Examiner B
D M FS
Age
D M FS
Age
No.
Mean
Range
Mean
Range
No.
M ean
Range
Mean
Range
97 81 89 84 83
1 1.92 10.90 11.82 10.96 12.12
0-51 0-42 0-58 0-45 0-62
10.99 10.89 1 1.23 11.12 1 1.73
6-17 5-18 5-17 6-17 6-16
84 85 86 74 97
5.82 6.82 6.87 7.31 7 .0 6
0-31 0-59 0-42 0.40 0.64
10.22 10.27 10.79 10.54 10.70
5-17 6-16 6-16 5-17 6-16
84 71 82 76 69
10.54 10.92 12.23
0-51 0-39 0-58 0-45 0-62
10.69 11.08 1 1.24 1 1.30 1 1.35
6-16 6-17 6-17 6-17 6-16
85 82 82 68 74
5.28 6.45 6.89 6 .6 0 6.59
0-31 0-50 0-70 0-37 0-30
10.04 10.27 10.63 10.35 10.29
5-17 6-18 6-16 5-17 6-16
14 Months
Control Pf P f “f- Dp Pf + T f P f 4“ T f 4“ D f S6 Months
Control Pf P f 4“ D f Pf + T f Pf + T f +
Df
1 1.00 1 1.67
out the study. A seven-film bitewing radiograph and a clinical examination were made at the 24month and 36-month intervals, but each subject received his assigned treatment at intervals of 18, 24, and 30 months even though no dental caries examinations were made at the 18-month and 30-month period. Subjects who missed the 24month examination but who did receive all neces sary treatments at the proper intervals were in cluded in the 36-month data if examined. At each examination period, subjects were given a new toothbrush and supply of dentifrice calculated to last 6 to 8 weeks, and they were instructed to return for more when they needed it.
Table 2
Results and discussion Group balance in terms of initial DMF surfaces and age for those subjects remaining in the study at the end of 24 and 36 months is shown in Table 1. Group balance information for the 6-month and 1-year data has already been re ported.1 The mean age of subjects examined by Examiner A is somewhat older than that of sub jects examined by Examiner B. In part, this may account for the higher prevalence rates found by Examiner A. In previous studies, however, Examiner A scored more caries than Examiner
D M F and D M FS increments for Examiners A and B after 24 months
% Group
No.
D M FT
Reduction
% p*
DM FS
Reduction
Examiner A Pf P f “1“ D f P f 4“ T f P f 4* T f 4“ D f
Control
81 89 84 83 97
2.7 5 2.5 5 2.33 1.22 3.60
(.3 0 0 ) t (.2 7 4 ) (.2 3 9 ) (.1 8 3 ) (.2 8 1 )
23.6 29.2 35.3 66.1
.03 80 .00 760 .00048 < .0 0 0 0 1
5.52 5.08 4.95 2.39 8.05
(.5 3 8 ) (.4 7 0 ) (.4 5 4 ) (.3 2 7 ) (.5 9 8 )
31.4 36.9 38.5 70.3
.00 180 .00007 .00003 < .00001
85 86 74 97 84
2.58 3 .02 2.1 6 1.99 4.0 0
(.2 2 8 ) (.2 6 5 ) (.2 4 5 ) (.1 9 4 ) (.3 4 3 )
35.5 24.5 46.0 50.2
.00 046 .0240 .00001 < .0 0 0 0 1
5.07 5.51 4.59 3.60 8.07
(.4 5 5 ) (.4 7 6 ) (.5 0 1 ) (.3 7 4 ) (.7 4 0 )
37.2 31.7 43.1 55.4
.00 046 .00 350 .00007 < .00001
Examiner B Pf P f 4” D f P f 4“ T f P f 4" T f -I" D f
Control
*A II p values are in relation to control group, tNum ber in parenthesis is standard error of mean. Bixler and M uhler: T H R E E SnF2 P R E P A R A T IO N S • 393
Table 3
D M FT and D M FS increments of 24 months— examiners combined D M FT
No.
Control
181 166 175 158 180
Pf
P f 4- Dp P f "I" T f P f 4“ T f -f" Dp
DMFS
Mean
Standard error of mean
3.80 2.66 2.78 2.24 1.60
.222 .188 .190 .171 .133
B.2 During this 3-year period, the overall sub ject loss for Examiner A was 35 per cent; for Examiner B, 36 per cent. These figures do not seem high considering that the treatment and examination interval was required to be 6 months plus or minus 2 weeks, in order for the subjects to remain eligible for the study. The increments observed at the end of 24 months in terms of the DMFT and DMFS indexes for both examiners are summarized in Table 2. For both examiners, the increments in all the various treatment groups were significantly lower than the control. This finding confirms the obser vations made previously at 6 months and 12 months. Using the DMFS index, Examiner A found that the group receiving the three topical treatments had a 70 per cent caries reduction as compared with the control, and this value was 22 to 29 per cent greater than that of the other treatment groups. Examiner B also observed the greatest caries reduction (55 per cent) in the three-treatment group (PF + TF + DF), as com pared with the other 1-treatment and 2-treatment groups. This result confirmed the previous find ing.1
Table 4
% Reduction
30.0 26.8 41.4 57.9
Standard error of mean
Mean
8.06 5.30 5.30 4.77 3.00
.476 .352 .334 .338 .249
24-month DMFS Control
Control Pf Pf + Df Pf + T f P f “t- T f “I" D f
Pf
< .00001 < < < <
.00001 .00001 .00001 .00001
N.S. .0232 < .00001
P f “t” D f
< .00001 N .S.* N.S. .00002
P f + T f P f -f- Tp -f- D f
< .00001 N.S. N.S.
< .00001 < .00001 < .00001 .00001
.0238
*N.S. not significant at 0.05 level of confidence. All values are derived from standard error of difference between means of two groups. 394 • JA D A , Vol. 72, Feb. 1966
34.2 34.2 40.8 62.8
Table 3 summarizes the results obtained when the DMFT and DMFS increments found by the two examiners are combined. This procedure was considered valid since the original treatment as signment was made on a random basis and, in addition, the ranking of the treatment groups by each examiner was similar. These data show that the results for the examin ers combined are essentially the same as those presented for the examiners individually. Table 4 presents results of a statistical analysis of the intergroup comparisons presented in Table 3. Each of the four treatment groups had a signifi cantly lower caries increment, as compared with the control group. Although the two 2-treatment groups (PF + Df , P p + Tf ) were not signifi cantly different from PF alone, the 3-treatment group (PF + T f -f Df ) was significantly more anticariogenic than the two 2-treatment groups and the single treatment group (PF). Table 5 summarizes results obtained at 36 months for the two examiners separately. These data parallel the findings at 24 months, with one exception. Examiner B did not rank the PF + T F and PF + TF + DF groups the same as at 24
Statistical analysis of intergroup comparisons using D M FS index
36-month DM FS
% Reduction
probabilities
Table 5
D M FT and D M FS increments scored by Examiners A and B after 36 months
% Group
N
D M FT
Reduction
% p*
D M FS
Reduction
Examiner A Pf P f 4"" D f Pf + T f Pf 4“ T f 4" D f
Control
71 82 76 69 84
3.58 3.27 3.05 1.83 5.02
(.355) t (.345) (.278) (.232) (.392)
29.1 34.9 39.2 63.5
.00580 .00070 .00003 < .00001
7.48 (.643) 6.77 (.641 ) 6.66 (.596) 3.67 (.366) 11.04 (.923)
29.1 38.7 39.7 66.8
82 82 68 74 85
3.45 3.60 2.24 2.74 5.36
(.269) (.336) (.243) (.277) [391)
35.6 32.8 58.2 48.9
.00005 .00062 < .00001 < .00001
6.77 6.96 4.84 5.46 10.89
37.8 36.1 55.6 49.9
.00150
.00012 .00005
< .00001
Examiner B Pf P f 4“ D f P f 4- T f P f 4“ T f 4" D f
Control
(.614) (.642) (.565) (.537) (.894)
.0001 1 .00028
< .00001
< .00001
*A II p values in relation to control group. tNum ber in parenthesis is standard error of the mean.
months. At this latter interval the 3-treatment group was a significantly more anticariogenic com bination than either of the two 2-treatment groups. At 36 months, however, the 2-treatment group, Pf + TV, was ranked higher in anticariogenicity than the 3-treatment group, although this differ ence was not statistically significant (0.42). The number of subjects remaining in these last two groups after 36 months was reduced to approxi mately 56 per cent of the original sample. This dropout rate was somewhat disproportionate since the other three groups (control, PF, and PF + Df ) had a 30 to 32 per cent dropout compared with 44 per cent for PF + T f and 43 per cent for PF + T f + DF. It is possible that this dis proportionate dropout might have influenced the findings observed in these last two groups. When
an examination of the dropout records in all five groups was made, it revealed that in the PF 4T f + Dr treatment group, 19 of the 23 dropouts during the last year were subjects who had previ ously demonstrated a below-the-mean caries in crement. It is impossible to say with certainty what effect the apparently nonrepresentative drop out has had on the results obtained, but the find ings are suggestive. When the findings of the two examiners are combined (Table 6), the data of 36 months ap pear similar to those obtained at 24 months with the 3-treatment group showing the greatest overall caries reduction of any of the other groups. Table 4 shows the statistical intergroup comparisons in which it can be noted that the P f + T F treat ment was significantly better than P p treatment
\
Table 6
D M FT and D M FS increments a t 36 months— examiners combined
D M FT
Group
C on trol Pf P f 4“ D f P f 4“ T f P f 4“ T f 4 " D f
No.
Mean
169 153 164 144 143
5.19 3.50 3.44 2.64 2.28
DM FS
Standard error of mean
.279 .223 .241 .185 .180
% Reduction
Mean
Standard error of mean
32.5 33.8 49.0 56.0
10.95 7.12 6.86 5.75 4.56
.642 .469 .454 .411 .325
% Reduction
35.0 37.4 47.6 58.4
Bixler and M uhler: Three SnF2 P R E P A R A T IO N S • 395
alone, a change from the 24-month observation. At each interval, the 3-treatment group was sig nificantly better than either of the two 2-treatment groups (P f + T f and PF + DF). These results indicate that the most effective use of topical stannous fluoride therapy is achieved in a nonfluoridated community when a combina tion of all three topical technics is used—the prophylaxis with a Snp 2-containing compatible pumice, followed immediately by an 8 per cent topical SnF2 application, and the home use of SnF2 in a proved, compatible dentifrice formula tion. Interestingly, Gish and Muhler3 observed that when the combination of all three SnF2 topical treatments described here was administered to children already receiving the benefits of fluoride in their communal water supply, these same levels of caries reductions were found over and above the effects of water fluoridation.
■H
Summary
A clinical study was conducted over a threeyear period in which children ranging in age from 5 to 18 years were given a series of treatm ents using a prophylactic paste con taining Sn F2, topically applied Sn F2/ and a Sn F 2-Ca 2P 207 dentifrice for home use. Two
different examiners each examined approxi m ately half of the 1,250 children. A t the end of three years, the children who received a com bination of all three forms of SnF2 therapy had the greatest reduction jn dental caries. Children receiving only 2 treatm ents (pro phylaxis paste and dentifrice or prophylaxis paste and topical stannous fluoride) or a single treatm ent (prophylaxis p a s te ), experi enced significantly less caries reductions com pared with the 3-treatm ent group.
This study was supported in part by a grant from the Procter Cr Gamble Company, Cincinnati. Doctors Bixler and Muhler are from the department of biochemistry, Indiana University Medical Center, In dianapolis. 1. Bixler, David, and Muhler, J. C. Effect on dental caries in children in a nonfluoride area of: combined use of three agents containing stannous fluoride: a prophylactic paste, a solution and a dentifrice. JA D A 68:792 June, 1964. 2. Bixler, David, and Muhler, J . C. Experimental clinical human caries test design and interpretation. JA D A 65:482 Oct., 1962. 3. Gish, C. W ., and Muhler, J . C. Effect on dental caries in children in a natural fluoride area of: com bined use of three agents containing stannous fluoride: a prophylactic paste, a solution and a dentifrice. JA D A 70:914 April, 1965.
Changes in Insurance A s a result of the enactment of Medicare, far-reaching changes in the patterns of health insurance lie ahead. They will affect not only the elderly but all age groups. . . . Commercial insurers foresee that the new law will serve as a base for a boom in their industry— not so much through the insuring of more people as through improvement and expansion of existing coverage for younger people who will no longer be satisfied with fewer benefits than those provided for their parents. . . . Blue Cross plans, too, are soon likely to offer a wide range of new benefits to their younger subscribers. . . . M any union leaders feel there is also considerable room for improvement in the field of disability income . . . there is still a huge money gap to be filled, and with the newly heightened public consciousness of health insurance, many moves are sure to be made to fill It.
Changing role o f health insurance, M edical W orld News, Sept. 3, 1965; reported in Health Insurance Institute, Editorial Round-Up, Sept. 10, 1965. ----------------------;-----------------------3—
39$ • JA PA , V p I, 72, Feb: 1966
David Bixler, DDS, PhD Joseph C. M uhler, DDS, PhD, Indianapolis
In a clinical study conducted during 3 years in a nonfluoride community, children were given treatm ent using a prophylactic paste containing stannous fluoride, topically applied stannous fluoride, and a stannous fluoridecalcium pyrophosphate dentifrice for home use. Findings show that the children receiving all three forms of therapy had the greatest reduction in dental caries. These results, which verify data found in a previous 1-year study, indicate that the most effective use of topical stannous fluoride therapy In a non fluoridated com m unity takes place when a combination of all three technics is used.
In a previous report,1 data were presented dem onstrating the clinical effectiveness of combining three topical technics of applying stannous fluoride for reducing the dental caries experience in chil dren residing in a nonfluoride area. These three 392
technics involved adding stannous fluoride to a compatible lava pumice prophylactic paste, stan nous fluoride applied in an aqueous solution after a dental prophylaxis, stannous fluoride as a con stituent of a dentifrice containing calcium pyro phosphate as the polishing agent. Results at the end of a year indicated that the combination of all three technics was the most effective way to use stannous fluoride in reducing dental caries. This paper reports data obtained in this study at the end of 2 and 3 years.
M ethods The clinical design and conduct of the study dur ing the second and third clinical years was the same as reported for the first year of the pro gram.1 Briefly, the experimental groups were as follows: group 1 received 8.9 per cent SnF2 lava pumice prophylactic paste, designated PF; group 2 received PF plus SnF2 dentifrice for home use, designated DF; group 3 received PF plus a topical application of an 8 per cent aqueous solution of SnF2, designated TF; group 4 received PF + DF + Tf ; group 5 served as the control and- received the appropriate placebo treatments. Groups 1 and 3 also received the placebo dentifrice. Two examiners were employed, each to ex amine a specific segment of each group through
T ab le 1
Balance in terms of initial D M FS and age for subjects completing 24 and 36 months in the study Examiner A
Group
Examiner B
D M FS
Age
D M FS
Age
No.
Mean
Range
Mean
Range
No.
M ean
Range
Mean
Range
97 81 89 84 83
1 1.92 10.90 11.82 10.96 12.12
0-51 0-42 0-58 0-45 0-62
10.99 10.89 1 1.23 11.12 1 1.73
6-17 5-18 5-17 6-17 6-16
84 85 86 74 97
5.82 6.82 6.87 7.31 7 .0 6
0-31 0-59 0-42 0.40 0.64
10.22 10.27 10.79 10.54 10.70
5-17 6-16 6-16 5-17 6-16
84 71 82 76 69
10.54 10.92 12.23
0-51 0-39 0-58 0-45 0-62
10.69 11.08 1 1.24 1 1.30 1 1.35
6-16 6-17 6-17 6-17 6-16
85 82 82 68 74
5.28 6.45 6.89 6 .6 0 6.59
0-31 0-50 0-70 0-37 0-30
10.04 10.27 10.63 10.35 10.29
5-17 6-18 6-16 5-17 6-16
14 Months
Control Pf P f “f- Dp Pf + T f P f 4“ T f 4“ D f S6 Months
Control Pf P f 4“ D f Pf + T f Pf + T f +
Df
1 1.00 1 1.67
out the study. A seven-film bitewing radiograph and a clinical examination were made at the 24month and 36-month intervals, but each subject received his assigned treatment at intervals of 18, 24, and 30 months even though no dental caries examinations were made at the 18-month and 30-month period. Subjects who missed the 24month examination but who did receive all neces sary treatments at the proper intervals were in cluded in the 36-month data if examined. At each examination period, subjects were given a new toothbrush and supply of dentifrice calculated to last 6 to 8 weeks, and they were instructed to return for more when they needed it.
Table 2
Results and discussion Group balance in terms of initial DMF surfaces and age for those subjects remaining in the study at the end of 24 and 36 months is shown in Table 1. Group balance information for the 6-month and 1-year data has already been re ported.1 The mean age of subjects examined by Examiner A is somewhat older than that of sub jects examined by Examiner B. In part, this may account for the higher prevalence rates found by Examiner A. In previous studies, however, Examiner A scored more caries than Examiner
D M F and D M FS increments for Examiners A and B after 24 months
% Group
No.
D M FT
Reduction
% p*
DM FS
Reduction
Examiner A Pf P f “1“ D f P f 4“ T f P f 4* T f 4“ D f
Control
81 89 84 83 97
2.7 5 2.5 5 2.33 1.22 3.60
(.3 0 0 ) t (.2 7 4 ) (.2 3 9 ) (.1 8 3 ) (.2 8 1 )
23.6 29.2 35.3 66.1
.03 80 .00 760 .00048 < .0 0 0 0 1
5.52 5.08 4.95 2.39 8.05
(.5 3 8 ) (.4 7 0 ) (.4 5 4 ) (.3 2 7 ) (.5 9 8 )
31.4 36.9 38.5 70.3
.00 180 .00007 .00003 < .00001
85 86 74 97 84
2.58 3 .02 2.1 6 1.99 4.0 0
(.2 2 8 ) (.2 6 5 ) (.2 4 5 ) (.1 9 4 ) (.3 4 3 )
35.5 24.5 46.0 50.2
.00 046 .0240 .00001 < .0 0 0 0 1
5.07 5.51 4.59 3.60 8.07
(.4 5 5 ) (.4 7 6 ) (.5 0 1 ) (.3 7 4 ) (.7 4 0 )
37.2 31.7 43.1 55.4
.00 046 .00 350 .00007 < .00001
Examiner B Pf P f 4” D f P f 4“ T f P f 4" T f -I" D f
Control
*A II p values are in relation to control group, tNum ber in parenthesis is standard error of mean. Bixler and M uhler: T H R E E SnF2 P R E P A R A T IO N S • 393
Table 3
D M FT and D M FS increments of 24 months— examiners combined D M FT
No.
Control
181 166 175 158 180
Pf
P f 4- Dp P f "I" T f P f 4“ T f -f" Dp
DMFS
Mean
Standard error of mean
3.80 2.66 2.78 2.24 1.60
.222 .188 .190 .171 .133
B.2 During this 3-year period, the overall sub ject loss for Examiner A was 35 per cent; for Examiner B, 36 per cent. These figures do not seem high considering that the treatment and examination interval was required to be 6 months plus or minus 2 weeks, in order for the subjects to remain eligible for the study. The increments observed at the end of 24 months in terms of the DMFT and DMFS indexes for both examiners are summarized in Table 2. For both examiners, the increments in all the various treatment groups were significantly lower than the control. This finding confirms the obser vations made previously at 6 months and 12 months. Using the DMFS index, Examiner A found that the group receiving the three topical treatments had a 70 per cent caries reduction as compared with the control, and this value was 22 to 29 per cent greater than that of the other treatment groups. Examiner B also observed the greatest caries reduction (55 per cent) in the three-treatment group (PF + TF + DF), as com pared with the other 1-treatment and 2-treatment groups. This result confirmed the previous find ing.1
Table 4
% Reduction
30.0 26.8 41.4 57.9
Standard error of mean
Mean
8.06 5.30 5.30 4.77 3.00
.476 .352 .334 .338 .249
24-month DMFS Control
Control Pf Pf + Df Pf + T f P f “t- T f “I" D f
Pf
< .00001 < < < <
.00001 .00001 .00001 .00001
N.S. .0232 < .00001
P f “t” D f
< .00001 N .S.* N.S. .00002
P f + T f P f -f- Tp -f- D f
< .00001 N.S. N.S.
< .00001 < .00001 < .00001 .00001
.0238
*N.S. not significant at 0.05 level of confidence. All values are derived from standard error of difference between means of two groups. 394 • JA D A , Vol. 72, Feb. 1966
34.2 34.2 40.8 62.8
Table 3 summarizes the results obtained when the DMFT and DMFS increments found by the two examiners are combined. This procedure was considered valid since the original treatment as signment was made on a random basis and, in addition, the ranking of the treatment groups by each examiner was similar. These data show that the results for the examin ers combined are essentially the same as those presented for the examiners individually. Table 4 presents results of a statistical analysis of the intergroup comparisons presented in Table 3. Each of the four treatment groups had a signifi cantly lower caries increment, as compared with the control group. Although the two 2-treatment groups (PF + Df , P p + Tf ) were not signifi cantly different from PF alone, the 3-treatment group (PF + T f -f Df ) was significantly more anticariogenic than the two 2-treatment groups and the single treatment group (PF). Table 5 summarizes results obtained at 36 months for the two examiners separately. These data parallel the findings at 24 months, with one exception. Examiner B did not rank the PF + T F and PF + TF + DF groups the same as at 24
Statistical analysis of intergroup comparisons using D M FS index
36-month DM FS
% Reduction
probabilities
Table 5
D M FT and D M FS increments scored by Examiners A and B after 36 months
% Group
N
D M FT
Reduction
% p*
D M FS
Reduction
Examiner A Pf P f 4"" D f Pf + T f Pf 4“ T f 4" D f
Control
71 82 76 69 84
3.58 3.27 3.05 1.83 5.02
(.355) t (.345) (.278) (.232) (.392)
29.1 34.9 39.2 63.5
.00580 .00070 .00003 < .00001
7.48 (.643) 6.77 (.641 ) 6.66 (.596) 3.67 (.366) 11.04 (.923)
29.1 38.7 39.7 66.8
82 82 68 74 85
3.45 3.60 2.24 2.74 5.36
(.269) (.336) (.243) (.277) [391)
35.6 32.8 58.2 48.9
.00005 .00062 < .00001 < .00001
6.77 6.96 4.84 5.46 10.89
37.8 36.1 55.6 49.9
.00150
.00012 .00005
< .00001
Examiner B Pf P f 4“ D f P f 4- T f P f 4“ T f 4" D f
Control
(.614) (.642) (.565) (.537) (.894)
.0001 1 .00028
< .00001
< .00001
*A II p values in relation to control group. tNum ber in parenthesis is standard error of the mean.
months. At this latter interval the 3-treatment group was a significantly more anticariogenic com bination than either of the two 2-treatment groups. At 36 months, however, the 2-treatment group, Pf + TV, was ranked higher in anticariogenicity than the 3-treatment group, although this differ ence was not statistically significant (0.42). The number of subjects remaining in these last two groups after 36 months was reduced to approxi mately 56 per cent of the original sample. This dropout rate was somewhat disproportionate since the other three groups (control, PF, and PF + Df ) had a 30 to 32 per cent dropout compared with 44 per cent for PF + T f and 43 per cent for PF + T f + DF. It is possible that this dis proportionate dropout might have influenced the findings observed in these last two groups. When
an examination of the dropout records in all five groups was made, it revealed that in the PF 4T f + Dr treatment group, 19 of the 23 dropouts during the last year were subjects who had previ ously demonstrated a below-the-mean caries in crement. It is impossible to say with certainty what effect the apparently nonrepresentative drop out has had on the results obtained, but the find ings are suggestive. When the findings of the two examiners are combined (Table 6), the data of 36 months ap pear similar to those obtained at 24 months with the 3-treatment group showing the greatest overall caries reduction of any of the other groups. Table 4 shows the statistical intergroup comparisons in which it can be noted that the P f + T F treat ment was significantly better than P p treatment
\
Table 6
D M FT and D M FS increments a t 36 months— examiners combined
D M FT
Group
C on trol Pf P f 4“ D f P f 4“ T f P f 4“ T f 4 " D f
No.
Mean
169 153 164 144 143
5.19 3.50 3.44 2.64 2.28
DM FS
Standard error of mean
.279 .223 .241 .185 .180
% Reduction
Mean
Standard error of mean
32.5 33.8 49.0 56.0
10.95 7.12 6.86 5.75 4.56
.642 .469 .454 .411 .325
% Reduction
35.0 37.4 47.6 58.4
Bixler and M uhler: Three SnF2 P R E P A R A T IO N S • 395
alone, a change from the 24-month observation. At each interval, the 3-treatment group was sig nificantly better than either of the two 2-treatment groups (P f + T f and PF + DF). These results indicate that the most effective use of topical stannous fluoride therapy is achieved in a nonfluoridated community when a combina tion of all three topical technics is used—the prophylaxis with a Snp 2-containing compatible pumice, followed immediately by an 8 per cent topical SnF2 application, and the home use of SnF2 in a proved, compatible dentifrice formula tion. Interestingly, Gish and Muhler3 observed that when the combination of all three SnF2 topical treatments described here was administered to children already receiving the benefits of fluoride in their communal water supply, these same levels of caries reductions were found over and above the effects of water fluoridation.
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Summary
A clinical study was conducted over a threeyear period in which children ranging in age from 5 to 18 years were given a series of treatm ents using a prophylactic paste con taining Sn F2, topically applied Sn F2/ and a Sn F 2-Ca 2P 207 dentifrice for home use. Two
different examiners each examined approxi m ately half of the 1,250 children. A t the end of three years, the children who received a com bination of all three forms of SnF2 therapy had the greatest reduction jn dental caries. Children receiving only 2 treatm ents (pro phylaxis paste and dentifrice or prophylaxis paste and topical stannous fluoride) or a single treatm ent (prophylaxis p a s te ), experi enced significantly less caries reductions com pared with the 3-treatm ent group.
This study was supported in part by a grant from the Procter Cr Gamble Company, Cincinnati. Doctors Bixler and Muhler are from the department of biochemistry, Indiana University Medical Center, In dianapolis. 1. Bixler, David, and Muhler, J. C. Effect on dental caries in children in a nonfluoride area of: combined use of three agents containing stannous fluoride: a prophylactic paste, a solution and a dentifrice. JA D A 68:792 June, 1964. 2. Bixler, David, and Muhler, J . C. Experimental clinical human caries test design and interpretation. JA D A 65:482 Oct., 1962. 3. Gish, C. W ., and Muhler, J . C. Effect on dental caries in children in a natural fluoride area of: com bined use of three agents containing stannous fluoride: a prophylactic paste, a solution and a dentifrice. JA D A 70:914 April, 1965.
Changes in Insurance A s a result of the enactment of Medicare, far-reaching changes in the patterns of health insurance lie ahead. They will affect not only the elderly but all age groups. . . . Commercial insurers foresee that the new law will serve as a base for a boom in their industry— not so much through the insuring of more people as through improvement and expansion of existing coverage for younger people who will no longer be satisfied with fewer benefits than those provided for their parents. . . . Blue Cross plans, too, are soon likely to offer a wide range of new benefits to their younger subscribers. . . . M any union leaders feel there is also considerable room for improvement in the field of disability income . . . there is still a huge money gap to be filled, and with the newly heightened public consciousness of health insurance, many moves are sure to be made to fill It.
Changing role o f health insurance, M edical W orld News, Sept. 3, 1965; reported in Health Insurance Institute, Editorial Round-Up, Sept. 10, 1965. ----------------------;-----------------------3—
39$ • JA PA , V p I, 72, Feb: 1966