Preventive Measures
Commutiity Dent. Oral Epidemiol. 1975: 3; 201-207 (Key words: denial caries: jtuoridcs; moulh rinsing; public hcallh denlislry;
loolhhrnstiing)
Effect of mouth rinsing and toothbrushing with fiuoride solutions on caries among Norwegian schoolchildren J. M . BiRKELAND AND L. JORKJEND Dental Itistitute oj Experimental Research, University oj Oslo, Blindern, Oslo, Norway ABSTRACT - Tfie caries experience and the plaque and gingival conditions of 14-year-old children participating in fortnightly fluoride (0.2 % NaF) mouth rinsing (88 subjects) were compared with observations in children performing supervised toothbrushing with a fluoride (0.5% NaF) solution 4-5 times per year {n = 90). Most of the children, 84 and 9 0 % respectively, had participated in these programs for the previous 6 years. Caries was assessed only on radiographs. The mean number of decayed surfaces was 5.8 (s.d. = 4.1, n = 88) and 5.4 (s.d. = 4.1, n = 90). The mean numbers of decayed and filled surfaces were 19.3 ± 9.2 and 27.9 ± 10.2 for suhjects with rinsing or brushing. This significant difference could not be ascribed to sex, social class, years of residence in the towns, number of dentists performing the previous treatments, toothbrushing habits, use of fluorides at home, or amount of plaque. All ehildren had gingivitis. There were no differences in the mean number of Plaque Index score 2 or the number of Gingival Index score 2 between the children with the different preventive programs. The girls' oral hygiene was better than the boys', but the gingival conditions were the same. Sex, social class, and toothbrushing techniques tended to have a slight influence on the amount of plaque. (Reeeived jor publication 13 Deeember 1974, aceepted 13 April 1975)
Fluoride mouth rinsing and supervised toothbrushing with fluoride solutions are widely used in caries preventive programs of public dental health services in Scandinavia. Apart from clitiical studies, information on the effect of these programs is sparse''"'"'^'. Moreover, no comparison of the benefits of such programs seems to have been carried out and a possible effect of the supervised brushing on the oral hygiene has been advertised for". The aim of the present study was to compare the oral hygiene, gingival condition, and caries experience of children taking part in preventive programs of fortnightly fluoride rinsing with those of childreti given supervised toothbrushing with fluoride 4-5 times yearly. .
MATERIAL AND METHODS Participants - The material consisted of 178 schoolchildren (Table 1) aged 14. The subjects were selected at random
from the pupils at five different schools (five dentists) in Porsgrunn (pop. 32,000) as well as Skien (pop. 45,000), Nonvay. The towns are located in the same area (8 km apart) and the demographic characteristics are much the same. The drinking water contains less than 0.05 parts/10" fluoride. Children undergoing orthodontic treatments were excluded. Preventive programs - Children in Porsgrunn participated in a program (started in 1964) with fortnightly fluoride mouth rinsings (10 ml of 0.2 % NaF). Toothbrushing instruction and motivation were carried out when the children entered the schools at the age of 7. The children were given fresh motivation and were reiiistructed during the yearly check-ups and dental treatments. The children in Skien participated in a preventive program (initiated in 1965) of four to five yearly supervised toothbrushings with a fluoride solution (0.5 % NaF). The supervised toothbrushing is assumed to improve the oral hygiene''. Motivation toward improved oral health was carried out at the check-ups. Participation in these programs exceeded 95 %. At the initiation of the programs, the mean numbers of tooth surfaces which had to be filled during the school year for
202
BiRKELAND AND JoRKJEND
Table 1. The distribution of 14-year-old children in Porsgrunn and Skien according to background characteristics Porsgrunn n = 88 n
Sex Girls Boys Sociat class Low Middle + high Years oj residence 1-2 3-5 6 or more Number oj dentists 1 2 3 or more Toothbrushing jrequeney Once daily Twice daily More than twice daily Toothbrushing technique
%
Skien n = 90 n
Total
178
%
52 (59) 36 (41)
47 (52) 43 (48)
99 79
57 (64) 31 (35)
66 (74) 24 (26)
123 55
5 ( 6) 9 (10) 74 (84)
1 ( 1) 8 ( 9) 81 (90)
6 17 155
17 (19) 48 (55) 23 (26)
5 ( 6) 27 (30) 58 (64)
22 75 81
13 (15) 65 (74)
21 (23) 59 (66)
34 124
10 ( 1 1 )
10 ( 1 1 )
20
Roll (R) Scrubh (S) Combination (R + S)
10 (21) 27 (31)
54 (60) 15 (17)
73 42
42 (48)
21 (23)
63
Use oj jluorides at home F-dentifrices F-rinse No F-vehicle
76 (87) 3(3) 9 (10)
74 (83) 3(3) 13 (14)
150 6 22
the 14-year-olds were 14.8 and 15.3 in Porsgrunn and Skien, respectively. In 1964 the mean DMFS score was 30 for 14-year-old children in Porsgrunn''. Dental status - Caries was assessed (L. J.) from dental radiographs (two bitewings -|- three films of maxillary anterior teeth) taken within the same period of a school term. The radiographs were taken by one operator, and viewed under standardized conditions. The caries experience on the proximal surfaces from mesial on the second molars to mesial on the first premolars, and the maxillary incisors were assessed. On the molars and premolars ocelusally as well as buccally (or lingually), only filled surfaces were recorded. A proximal surface was regarded as decayed when a radiolucent area could be seen^^. Judged from a pretest, the partial recording caused an underestimation amounting to 0.6 surfaces when compared with a DMFS score of 17 estimated in a complete clinical examination. Supragingival plaque and gingivitis were assessed at 48 tooth/gingival margins on the first molars and the incisors
by means of the Plaque and the Gingival Inde.x systems Baekground charaeteristies - On the basis of official information on the parents' occupation, the children were grouped into three social classes: high, middle, and low. Information about years of residence and number of dentists having performed previous treatments of caries was obtained from the dental public health service. The children were asked about toothbrushing habits and the use of fluorides at home. Evaluations - The number of Plaque and Gingival Index scores of 2 has been found to adequately describe the plaque and the gingival condition of children^i 8>'^. The number of decayed and filled surfaces was used as a dependent variable. A possible effect on the dependent variable by the independent variables of preventive program (town), sex, social class, years of residence in the town, number of dentists having performed the previous caries treatments, frequency of toothbrushing, brushing technique, and the use of fluoride vehicles at home was evaluated hy means of the program known as automatic interaction detection (AID). The number of Plaque Index scores of 2 was introduced as predictor by the analyses of the data on caries. Furthermore, the caries experience among the children was related to the dentists who performed the last dental treatments. A possible effect of the background characteristics on the dependent variables, of plaque and gingivitis was also assessed.
RESULTS BACKGROUND CHARACTERISTICS There were no marked differenees in the distribution of the independent variables, sex, social class, years of residence, toothbrushing frequency, and use of fluorides at home among children in Porsgrunn and Skien (Table 1). The percentage values in Table 1 are based on the number of participants from each town. Most of the children, 84 and 90 %, had been living in their towns for more than 6 years. Sixty-four percent of the children in Skien had received previous dental treatments by three dentists. Most of the children in Porsgrunn had been treated by two dentists. The children in Porsgrunn and Skien reported using different toothbrushing techniques (x' = 27.1, d.f. = 2). CARIES There was no difference in the number of decayed surfaces among the children in Porsgrunn and Skien (Table 2). The frequency distribution of decayed (Di) + filled (F) surfaces (DF, Fig. 1) as well as the DF on the proximal surfaces (Fig. 2) indicated a significantly different caries experience between the children in these towns (t = 5.91).
Two caries preventive programs 203 Table 2. The mean ( ±s.d.) number of decayed (D), filled ( F ) , and DFS surfaces (S) among 14-ycar-old children participating in preventive programs with fluoride mouth rinsing (10 ml of 0.2 % NaF) fortnightly (Porsgrunn) or 4-5 yearly toothbrushings with a fluoride solution (0.5 % NaF) (D) Decayed
Sex
Town Porsgrunn
Girls Boys
« = 52 n = 36
6.3 ± 3.7 5.1 ± 4.6
Skien
Girls Boys
n = 47 n = 43
5.3 + 3.4 5.4 ± 4.6
13.7 13.2 22.4 22.7
n = 178
5.5 ± 4.1
18.1 ± 9.3
Total
The reproducibility of the diagnoses amounted to 96%. Effect of the independent variables - Due to the small number of subjects in some classes of the independent variables, combinatiotis of classes were used for the predictors, social class, years of residence, and use of fluorides at home. The predictor town (preventive program) explained most of the variance in the DFS values (Table 3). The number of Plaque Index scores of 2 had no power to explain the caries experience. The predictors, years of residence, number of dentists having performed previous treatments, and toothbrushing technique, were shghtly explanatory (Table 3). The effects of these predictors were assessed separately for Porsgrunn and Skien. The analyses eonfirmed the strong explanatory power of the predictor town (Table 4). The children were compared in terms of the dentists who had performed the last dental treatments. The mean DFS scores ranged from 13.8 (s.d. =
FREQUENCY OF CHILDREN (%)
15
20
NUMBER
25 OF
DFS
Fig. 1. Frequency distribution of mean number of decayed (D) + filled (F) surfaces among 14-year-old children participating in caries preventive programs with fortnightly fluoride mouth rinsing (n = 88) or toothbrushing with fluoride solution 4—5 times per year {n = 90).
DFS
(F) Filled
± ± ± ±
5.6 8.5 9.3 9.0
19.9 18.3 27.7 28.1
± 7.7 ± 10.9 ±9.9 ± 10.4
23.6 ± 10.6
11, n = 12) to 20.5 (s.d. = 48, n = 11) in Porsgrunn and from 25.7 (s.d. = 10.7, n = 22) to 31.3 (s.d. = 10.2, n = 19) in Skien. The children from Porsgrunn with a DFS score of 10 or less (8.3 ±8.3, n = 18) were compared Table 3. The distribution of the mean ( ± s.d.) number of decayed and filled surfaces, DFS, among 14-year-old children according to background characteristics
Mean DFS ± s.d.
Total Town
= 178
Porsgrunn ;; = Skien n= Sex Girls • ;z = Boys n = Soeial elass Low ji = Middle-f-high n= Years oj re.sidetice 5 or less n= 6 or more n= Number oj dentists 1 n= 2 7! = 3 n= Toothbrustiing, teetinique Roll (R) n= Scrubb (S) n= Combination (R-FS) n= Toothbrushing jrequeney Once daily n = Twice daily n= More than twice n= Use oj jluorides at home F-dentifrices jj = No F-vehicle n =
Between sum of square/ total sum of square
23.6± 10.6
88 90
19.3 ± 9.2 27.9 ±10.2
0.17
99 79
23.6 ± 9.6 23.6 ±11.7
0.00
123 55
23.9 ±10.2 22.8 ±11.4
0.02
23 155
27.2 ± 9.6 23.1 ± 10.6
0.02
22 75 81
11.7 ± 8.3 22.1 ±10.2 26.7 ±10.5
0.07
73 42 63
26.5 ±10.8 21.5 ±10.5 21.7 ± 9.7
0.05
34 124 20
22.5 ±10.0 23.4 ±10.6 26.0 ±10.9
0.01
156 22
23.6 ±10.4 24.0 ± 8.8
0.03
204
BiRKELAND AND JoRKJEND
Table 4. The distribution of the mean DFS ( ±s.d.) among children in Porsgrunn and Skien according to three background characteristics Town
Years oj residence 5 or less 6 or more Number oj dentists perjorming treatments n =1
Toothbrushing technique Roll (R) Scrubh (S) Combination (R + S)
Porsgrunn 19.3 ± 9.2 {n
Skien 27.9 ± 10.2 {n = 90)
24.3 18.3
± 9.2 ± 8.8
(n = 14) (« = 74)
31.7 27.5
8.2 ± 10.3 ±
{n = 9) [n = 81)
16.4 ± 8.1 19.8 ± 9.5 20.3 ± 8.9
(n = 17) (n = 48) {n = 23)
22.2 ± 7.2 26.1 ± 10.1 29.2 ± 10.1
{n = 5) {n = 27) {n = 58)
19.5 ± 8.6 17.7 ± 9.3 20.1 ± 9.2
{n =19) (n = 27) {n = 42)
28.9 ± 10.4 28.3 ± 9.1 24.9 ± 9.8
{n = 54) [n = 15) {n = 21)
Girls in both towns had a lower number of Plaque Index scores of 2 than boys (Table 5 ) . Gingival Index scores of 0 and of 3 constituted only fractions of the recordings (Table 6 ) . Between girls and boys there were no differences in the number of the Gingival Index scores. Effect of background characteristics - The predictors sex, social class, number of dentists having performed previous treatments, toothbrushing technique, and toothbrushing frequency had a slight
explanatory power on the number of Plaque Index scores of 2 (Table 7 ) . Differences in the number of Gingival Index scores of 2 were partly explained by the toothbrushing frequency and the use of fluorides at home (Table 7 ). The children with from 0 to 10 or from 31 to 48 instances of Plaque Index seores of 2 were compared. The children from Skien constituted 59 % and 58 % of these subsamples, 51 % in the entire material. Girls were most frequent among children with few scores of 2 (Table 8, x" = 19.6, d.f. = 1). Subjects from the lowest social class tended to be more frequent among children with a high number of 2 scores (z^ = 3.5, d.f. = 1). Ghildren found to have between 31 and 48 Plaque Index scores of 2 had the highest number of Gingival Index scores of 2.
Table 5. The mean ( ± s.d.) number of the Plaque Index scores 0-3 among 14-year-old children participating in preventive programs with fortnightly fluoride (10 ml 0.2 % NaF) mouth rinsing (Porsgrunn) or 4-5 yearly toothbrushings with a fluoride solution (0.5 % NaF - Skien)
Table 6. The mean ( ± s.d.) number of Gingival Index scores of 0-3 among 14-year-old children participating in preventive programs with fortnightly fluoride (10 ml 0.2 % NaF) mouth rinsing (Porsgrunn) or 4-5 yearly toothbrushings with a fluoride solution (0.5 % NaF - Skien)
with participants from Skien with DFS of 40 or more (43.8 ± 2.9, n = 15). Social class had no marked explanatory power in this subsample (26.4 ± 18.7, n = 22 for the low social class vs. 20.5 ± 18.4, n = 11, mean for n = 3 3 : 24.4 ± 18.1). PLAQUE AND GINGIVITIS
Gingival Index score
Plaque Index score Towtifsex
7 ownjsex Porsgrunn Girls (n = Boys {n = Skien Girls (n = Boys {n =
0
1
2
52) 36)
15 + 10 9± 7
15 ±5 14±7
18+12 23 ±12
0.3 ±1.3 1.4±3.6
47) 43)
]5± 9
18±7 16±7
15 + 12 24±12
0.3+1.4 1.1±2.5
7±
8
0
3
Porsgrunn Girls (n = Boys {n = Skien Girls (n = Boys (n =
1
2
3
52) 36)
0. 8 ±3.0
31 ± 9 28 ±10
16± 9 0. 1 ± 0.7 19± 10 0.3±1.1
47) 43)
1. 5 ±5.5 30 ± 9 0. 7 ±4.7 31 ± 8
16± 8 0. l±0.3 16± 8 0. l±0.5
0
Two caries preventive programs 205 Table 7. The distribution of the mean number of Plaque and Gingival Index scores of 2 among 14-year-old children according to background characteristics. (BSS/TSS = Between sum of square/total sum of square) Plaque score 2 X ±'. i.d. '
Gingival score 2 X ± S;.d.
n = 178
BSS/ 19.2 ±12.4 TSS
16.5 ± 9.2
Skien
n = 88 ri = 90
19.8±11.8 !8.6±12.9 (0.00)
16.9 ± 10.0 16.0 ± 8.3
Sex Girls
n = 99
16.2 ±12.0 22.8 ±12.0 (0.07)
15.6± 9.0 17.5± 9.3
Total Town Porsgrunn
Boys tl — 79 Social class Low n = 123
16.5± 11.8 20.5 ± 12.6
16.7 ± 9.3 15.8 ± 9.0
18.0 ± 8.6 19.3 ± 12.9 (0.00)
16.3± 7.9 16.5 ± 9.3
15.9 ± 10.0 17.9 ±12.4 (0.02) 21.2±12.6
17.3 ± 11.3
19.7± 11.1 24.3 ± 11.9 (0.05)
17.0 ± 8.9 17.2± 9.7
15.4+ 11.1
15.4± 9.0
15.1 ± 11.6 18.1 ±12.1 (0.05)
15.9 ± 7.6 17.1 ± 9.7
16.5±13.3
13.8±:7.6
F-dentifrices + F-rinse n = 156 No F-vehicle
18.8 ±12.3
16.1 ± 9.0
22
21.7±12.7
Middle + high n = 55 Years oj residenci 5 or less n ~ 23 6 or more n = 155 Number oj dentists i'.r-n = 22 2 n ~ 75 3
n = 81
Toothbrushing techniques Roll (R) n = 73 Scrubb (S) n = 42
(0.02)
16.3± 16.4±
9.3 8.4
frequent in these subsamples. This finding strengthened the belief that there were marked variations in the oral hygiene of the children with supervised brushing. Children reporting using either the Roll or Scrubb teehnique tended to have a higher number of Plaque Scores of 2 than children using the combination of these techniques (Table 7). Regular attention as with fortnightly mouthrinsing has been assumed to motivate toward improved oral hygiene and gingival conditions"". However, weekly supervised toothbrushing has been found to have no beneficial effect on the oral hygiene and the gingival conditions compared to weekly rinsing". The present findings indicate that supervised brushing 4-5 times yearly had no better motivational effeets than fortnightly rinsing. CARIES The present radiographic examination causes an Table 8. The mean number of Gingival Index scores of 2 among 14-year-old children with less than 11 and more than 30 Plaque Index scores of 2. Maximum number of scores = 48 Number of Plaque Index scores of 2 0-10 31-48
Combination (R + S) 63
Toothbrushing frequeney Once daily n = 34 Twice daily n = 124 More than twice n = 20 Use oj jluorides at home
tl
=
(0.03)
19.1 ± 9.8
DISCUSSION PLAQUE AND GINGIVITIS All children in the present study had gingivitis and no variations in gingival conditions eould be ascribed to the preventive programs. Sex and toothbrushing habits explained most of the variances in the oral hygiene. The improved condition in girls was especially marked when children with the lowest and highest number of Plaque Index scores of 2 were compared. The children from Skien were most
Number of Gingival Index scores of 2 n = 54: n = 38:
11.9 ±7.2 Towti Porsgrunn Skien Sex Girls Boys Soeiat ctass Low Middle + high Toothbrushing techniques Roll (R) n= Scrubb (S) n= Gombination (R + S) n= Toothbrushing jrequeney Once daily Twice daily More than twice n=
22.4 ±9.2
22 32
11.7 ±8.2 « = 1 6 27.3 ± 9.7 12.0 ±6.4 71 = 22 19.0 ± 6.9
42 12
12.1±7.6 11.2±5.5
n = 12 21.4± 7.4 « = 26 22.9± 9.8
34 20
12.6±8.0 10.7±5.3
ti = 31 21.8± 8.6 n= 7 25.4±10.9
20 10
13.5 ±6.0 9.7±5.8
n = 17 20.1 ± 8.1 ?i = 15 23.6± 10.1
24
11.8±6.9
n= 6 26.3 ± 7.8
4 42
11.0±6.3 11.8 ±6.9
n = 1 2 18.4± 6.5 « = 22 25.7 ± 9.8
8
12.6 + 8.6
» = 4 16.5± 2.6
206
BiRKELAND AND JoRKJEND
100 80 MAXILLA 60
40
20
- 1=
= 2 =
—4 =
= 5 =
=6 =
:7
= 5 =
= 6=
--7
20
40 MANDIBLE
60 80 L
1 Fig. 2. Percentage of decayed and filled proximal surfaces among 14-year-old children participating in caries preventive programs with fortnightly fluoride (0.2 % NaF) mouth rinsing (hatched area) or toothbrushing with fluoride (0.5 % NaF) solutions 4-5 times per year (total area). Radiographic diagnosis. The mandibular incisors and the canines were not recorded. Each bar represents a tooth. Right side of bar gives data for distal surface, left side mesial surface.
underestimation, especially in subjects with high caries prevalence. An advantage of this method, however, is that it permits objective comparison in future studies'^. Comparison - Judging from the following considerations, the different earies experience of the children in the two towns is most likely related to the difference in the preventive programs: 1. The earies experiences eould not be ascribed to the predietors sex, soeial class, and use of fluoride at home. These variables had a similar distribution among the children in the two towns. The explanatory power of social class was still moderate when subjeets from Porsgrunn with the lowe.st earies experience were compared with those from Skien with the highest prevalenee. Aeeording to Scandinavian studies, certain factors in the home environments rather than the socioeconomic situa-
tion could be related to the caries experience of 14year-old children^'''*. 2. The different caries experiences in these towns were still evident when the dentists who performed the last treatments were introduced as predictor. The caries prevalences of the children may therefore hardly be eaused by different attitudes to restorative and preventive dentistry among the dentists in the towns. 3. There were different amounts of caries, but the distribution on the various proximal tooth surfaces was similar in both groups of children (Fig. 2). 4. There was a tendency toward lower caries prevalence among children who had been living in these towns for 6 years or more. This tendency was evident in both towns (Table 4) and verifies the effectiveness of the programs. On the other hand, the present caries experiences probably reflect the maximum benefits obtainable using the present programs in these populations. Reasons for benefits — A substantial caries reduction was found in children from Porsgrunn after the introduction of the caries preventive program^ The caries prevalence among children in the two towns may have been at the same level at the initiation of the preventive programs. This view is strengthened by the finding that 15 surfaces had to be filled in 14-year-old children in both towns at the introduction of the programs. Furthermore, no special demographic or social alterations have taken plaee in either of these towns during the past 10 years. The signifieantly different caries experience of the children in Porsgrunn and Skien is probably ascribable to the fluoride applications. Weekly or fortnightly fluoride mouth rinsings seem to give greater benefits'^''^''°'^'' than supervised toothbrushing with fluoride solutions 4-6 times per year"*'"'''•"'' ^\ The frequency of the fluoride applications rather than the fluoride ion concentration seems important''^ This view is in agreement with the assumed mode of action of the fluoride ions'* and the lack of a lasting anticaries effect when fluoride applications were interrupted"". Fluoride-containing dentifrices may have reduced the caries prevalence. This predictor, however, had the same distribution in both towns. The high proportion reporting to use fluoride at home exceeded previous findings in adult Norwegians^ This may be due to motivation of the children and/or overreporting.
Two caries preventive programs 207 A very low caries incidence has been found in children with proper oral hygiene^'". The predictor amount of plaque, however, had no ability to explain the caries experiences between or within the two towns. The different caries experience of the children with mouth rinsing and supervised toothbrushing is most likely related to the frequeneies of the fluoride applications rather than the rinsing and brushing
12. HoLLENDER, L. & KocH, G.: Roentgenographic partial recording of caries in assessment of effect of prophylactic measures. Odontot. Revy 1969: 20: 267-282.
per se.
15.
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E . : Supeivised
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tooth
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effect of sodium ferric and zirconium fluorides. A comparative study on school children using supervised brushing as the mode of application. Acta Odontol. Scand. 1964: 22: 401-413. 4. BiRKELAND, J. M.: In vitro study on the mechanisms of . action of fluoride in low concentrations. Caries Res. 1975: 9; 110-118. 5. BiRKELAND, J. M. & HELOE, L . A.: Use of fluorides and the learning of interdental cleaning. The dissemination of preventive dental health behavior among adult Norwegians. Community Dent. Oral Epidemiol. 1974: 2: '" 66-69. 6. BiRKELAND, J. M. &. JoRKjEND, L.: A new approach to the evaluation of Plaque Index scores. / . Periodontal Res. 1973: 8; 284-289. 7. BiRKELAND, J. M., JoRKjEND, L. & BROCH, L . : An approach to objective assessment of caries prophylactic •i measures in a dental health program. Community Dent. Oral Epidemiol. 1975: 5; in press. 8. BiRKELAND, J. M., JORKJEND, L. & FEHR, F . R . V. D.: The influence of fluoride mouth rinsing on the incidence of gingivitis in Norwegian children. Community Dent. Oral Epidemiot. 1973: / ; 17-21. 9. BuLLEN, D. C. T., McCoMDiE, F. & HOLE, L. W . : Twoyear effect of supervised toothbrushing with an acidulated fluoride-phosphate solution. / . Can. Dent. Assoe. ' 1966: 32: 89-93. 10. FoRSMAN, B. 1965: Effekten av munskjolningar med natriumfluoiidlosning vid skolar i Vaxjo. Sver. Tandtaek. Foerb. Tidn. 1965: 57: 705-709. 11. HEIEETZ, S. B., DRISCOLL, W . S. & CREIGIITON, W . E . :
The effect on dental caries of weekly rinsing with a neutral sodium fluoride or an acidulated phosphatefluoride mouthwash. / . Am. Dent. Assoc. 1973: 87; 364-368.
ViEGAS, A. R., GUIMARAES, L. O. C. & LoPES, E. S.: Evaluation of self-administered prophylaxis and supervised toothbrushing with acidulated phosphate fluoride. Caries Res. 1974: 8; 39-51. HuNSTADBRAATEN, K.: Tre ars erfaring med fluoridborsting av skolebarnas tenner i Modum. Nor. Tatinlaeg. Foren. Tid. 1966: 76: 164-173. KOCH, G . : Effect of sodium fluoride in dentifrice and mouthwash on incidence of dental caries in schoolchildren. Odontol. Revy 1967: 18: Suppl. 12. KOCH, G . : Caries increment in schoolchildren during and two years after end of supervised rinsing of the mouth with sodium fluoride solution. Odontol. Revy 1969: 20: 323-330. KoGH, G. & MARTINSSON, T . : Social background och dess inverkan pa kariesforekomsten hos skolbarn. En eiikaetundersokning. Sver. Tandlaek.-Foerb. Tidn. 1969: 6/; 786-792.
19. LINDHE, J. & AXELSSON, P.: The effect of controlled
oral hygiene and topical fluoride application on caries and gingivitis in Swedish schoolchildren. Community Dent. Oral Epidemiol. 1973: / ; 9-16. 20. LINDHE, J., KOCH, G . & MANSSON, U . : The effect of
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25.
supervised oral hygiene on the gingiva of children. Effect of mouth rinsings. / . Periodontal Res. 1966: 1: 268-275. LOE, H . & SILNESS, J.: Periodontal disease in pregnancy. I. Prevalenee and severity. Acta Odontol. Seand. 1963: 21: 533-551. MARTHALER, T . M . : Reduction of caries, gingivitis and calculus after eight years of preventive measures - Obseivations iu seven communities. Hetv. Odontot. Acta 1972: 16: 69-83. MARTHALER, T . M . : Improved oral health of schoolchildren of 16 communities after 8 years of prevention. I. Combining DMF data from the communities. Hetv. Odontot. Acta 1974: 18: 119-142. SILNESS, J. & LOE, H . : Periodontal disease in pregnancy. II. Correlation between oral hygiene and periodontal condition. Acta Odontol. Scand. 1964: 22: 121-135. ToRELL, P. & ERICSSON, Y . : Two-year clinical tests with different methods of local caries-preventive fluorine application in Swedish school-children. Aeta Odontot. Scand. 1965: 23: 287-322.
Address: Dental Institute oj Experimental Univer.nty oj Oslo Blindern Osto 3 Norway
Researeh
*
Commutiity Dent. Oral Epidemiol. 1975: 3; 201-207 (Key words: denial caries: jtuoridcs; moulh rinsing; public hcallh denlislry;
loolhhrnstiing)
Effect of mouth rinsing and toothbrushing with fiuoride solutions on caries among Norwegian schoolchildren J. M . BiRKELAND AND L. JORKJEND Dental Itistitute oj Experimental Research, University oj Oslo, Blindern, Oslo, Norway ABSTRACT - Tfie caries experience and the plaque and gingival conditions of 14-year-old children participating in fortnightly fluoride (0.2 % NaF) mouth rinsing (88 subjects) were compared with observations in children performing supervised toothbrushing with a fluoride (0.5% NaF) solution 4-5 times per year {n = 90). Most of the children, 84 and 9 0 % respectively, had participated in these programs for the previous 6 years. Caries was assessed only on radiographs. The mean number of decayed surfaces was 5.8 (s.d. = 4.1, n = 88) and 5.4 (s.d. = 4.1, n = 90). The mean numbers of decayed and filled surfaces were 19.3 ± 9.2 and 27.9 ± 10.2 for suhjects with rinsing or brushing. This significant difference could not be ascribed to sex, social class, years of residence in the towns, number of dentists performing the previous treatments, toothbrushing habits, use of fluorides at home, or amount of plaque. All ehildren had gingivitis. There were no differences in the mean number of Plaque Index score 2 or the number of Gingival Index score 2 between the children with the different preventive programs. The girls' oral hygiene was better than the boys', but the gingival conditions were the same. Sex, social class, and toothbrushing techniques tended to have a slight influence on the amount of plaque. (Reeeived jor publication 13 Deeember 1974, aceepted 13 April 1975)
Fluoride mouth rinsing and supervised toothbrushing with fluoride solutions are widely used in caries preventive programs of public dental health services in Scandinavia. Apart from clitiical studies, information on the effect of these programs is sparse''"'"'^'. Moreover, no comparison of the benefits of such programs seems to have been carried out and a possible effect of the supervised brushing on the oral hygiene has been advertised for". The aim of the present study was to compare the oral hygiene, gingival condition, and caries experience of children taking part in preventive programs of fortnightly fluoride rinsing with those of childreti given supervised toothbrushing with fluoride 4-5 times yearly. .
MATERIAL AND METHODS Participants - The material consisted of 178 schoolchildren (Table 1) aged 14. The subjects were selected at random
from the pupils at five different schools (five dentists) in Porsgrunn (pop. 32,000) as well as Skien (pop. 45,000), Nonvay. The towns are located in the same area (8 km apart) and the demographic characteristics are much the same. The drinking water contains less than 0.05 parts/10" fluoride. Children undergoing orthodontic treatments were excluded. Preventive programs - Children in Porsgrunn participated in a program (started in 1964) with fortnightly fluoride mouth rinsings (10 ml of 0.2 % NaF). Toothbrushing instruction and motivation were carried out when the children entered the schools at the age of 7. The children were given fresh motivation and were reiiistructed during the yearly check-ups and dental treatments. The children in Skien participated in a preventive program (initiated in 1965) of four to five yearly supervised toothbrushings with a fluoride solution (0.5 % NaF). The supervised toothbrushing is assumed to improve the oral hygiene''. Motivation toward improved oral health was carried out at the check-ups. Participation in these programs exceeded 95 %. At the initiation of the programs, the mean numbers of tooth surfaces which had to be filled during the school year for
202
BiRKELAND AND JoRKJEND
Table 1. The distribution of 14-year-old children in Porsgrunn and Skien according to background characteristics Porsgrunn n = 88 n
Sex Girls Boys Sociat class Low Middle + high Years oj residence 1-2 3-5 6 or more Number oj dentists 1 2 3 or more Toothbrushing jrequeney Once daily Twice daily More than twice daily Toothbrushing technique
%
Skien n = 90 n
Total
178
%
52 (59) 36 (41)
47 (52) 43 (48)
99 79
57 (64) 31 (35)
66 (74) 24 (26)
123 55
5 ( 6) 9 (10) 74 (84)
1 ( 1) 8 ( 9) 81 (90)
6 17 155
17 (19) 48 (55) 23 (26)
5 ( 6) 27 (30) 58 (64)
22 75 81
13 (15) 65 (74)
21 (23) 59 (66)
34 124
10 ( 1 1 )
10 ( 1 1 )
20
Roll (R) Scrubh (S) Combination (R + S)
10 (21) 27 (31)
54 (60) 15 (17)
73 42
42 (48)
21 (23)
63
Use oj jluorides at home F-dentifrices F-rinse No F-vehicle
76 (87) 3(3) 9 (10)
74 (83) 3(3) 13 (14)
150 6 22
the 14-year-olds were 14.8 and 15.3 in Porsgrunn and Skien, respectively. In 1964 the mean DMFS score was 30 for 14-year-old children in Porsgrunn''. Dental status - Caries was assessed (L. J.) from dental radiographs (two bitewings -|- three films of maxillary anterior teeth) taken within the same period of a school term. The radiographs were taken by one operator, and viewed under standardized conditions. The caries experience on the proximal surfaces from mesial on the second molars to mesial on the first premolars, and the maxillary incisors were assessed. On the molars and premolars ocelusally as well as buccally (or lingually), only filled surfaces were recorded. A proximal surface was regarded as decayed when a radiolucent area could be seen^^. Judged from a pretest, the partial recording caused an underestimation amounting to 0.6 surfaces when compared with a DMFS score of 17 estimated in a complete clinical examination. Supragingival plaque and gingivitis were assessed at 48 tooth/gingival margins on the first molars and the incisors
by means of the Plaque and the Gingival Inde.x systems Baekground charaeteristies - On the basis of official information on the parents' occupation, the children were grouped into three social classes: high, middle, and low. Information about years of residence and number of dentists having performed previous treatments of caries was obtained from the dental public health service. The children were asked about toothbrushing habits and the use of fluorides at home. Evaluations - The number of Plaque and Gingival Index scores of 2 has been found to adequately describe the plaque and the gingival condition of children^i 8>'^. The number of decayed and filled surfaces was used as a dependent variable. A possible effect on the dependent variable by the independent variables of preventive program (town), sex, social class, years of residence in the town, number of dentists having performed the previous caries treatments, frequency of toothbrushing, brushing technique, and the use of fluoride vehicles at home was evaluated hy means of the program known as automatic interaction detection (AID). The number of Plaque Index scores of 2 was introduced as predictor by the analyses of the data on caries. Furthermore, the caries experience among the children was related to the dentists who performed the last dental treatments. A possible effect of the background characteristics on the dependent variables, of plaque and gingivitis was also assessed.
RESULTS BACKGROUND CHARACTERISTICS There were no marked differenees in the distribution of the independent variables, sex, social class, years of residence, toothbrushing frequency, and use of fluorides at home among children in Porsgrunn and Skien (Table 1). The percentage values in Table 1 are based on the number of participants from each town. Most of the children, 84 and 90 %, had been living in their towns for more than 6 years. Sixty-four percent of the children in Skien had received previous dental treatments by three dentists. Most of the children in Porsgrunn had been treated by two dentists. The children in Porsgrunn and Skien reported using different toothbrushing techniques (x' = 27.1, d.f. = 2). CARIES There was no difference in the number of decayed surfaces among the children in Porsgrunn and Skien (Table 2). The frequency distribution of decayed (Di) + filled (F) surfaces (DF, Fig. 1) as well as the DF on the proximal surfaces (Fig. 2) indicated a significantly different caries experience between the children in these towns (t = 5.91).
Two caries preventive programs 203 Table 2. The mean ( ±s.d.) number of decayed (D), filled ( F ) , and DFS surfaces (S) among 14-ycar-old children participating in preventive programs with fluoride mouth rinsing (10 ml of 0.2 % NaF) fortnightly (Porsgrunn) or 4-5 yearly toothbrushings with a fluoride solution (0.5 % NaF) (D) Decayed
Sex
Town Porsgrunn
Girls Boys
« = 52 n = 36
6.3 ± 3.7 5.1 ± 4.6
Skien
Girls Boys
n = 47 n = 43
5.3 + 3.4 5.4 ± 4.6
13.7 13.2 22.4 22.7
n = 178
5.5 ± 4.1
18.1 ± 9.3
Total
The reproducibility of the diagnoses amounted to 96%. Effect of the independent variables - Due to the small number of subjects in some classes of the independent variables, combinatiotis of classes were used for the predictors, social class, years of residence, and use of fluorides at home. The predictor town (preventive program) explained most of the variance in the DFS values (Table 3). The number of Plaque Index scores of 2 had no power to explain the caries experience. The predictors, years of residence, number of dentists having performed previous treatments, and toothbrushing technique, were shghtly explanatory (Table 3). The effects of these predictors were assessed separately for Porsgrunn and Skien. The analyses eonfirmed the strong explanatory power of the predictor town (Table 4). The children were compared in terms of the dentists who had performed the last dental treatments. The mean DFS scores ranged from 13.8 (s.d. =
FREQUENCY OF CHILDREN (%)
15
20
NUMBER
25 OF
DFS
Fig. 1. Frequency distribution of mean number of decayed (D) + filled (F) surfaces among 14-year-old children participating in caries preventive programs with fortnightly fluoride mouth rinsing (n = 88) or toothbrushing with fluoride solution 4—5 times per year {n = 90).
DFS
(F) Filled
± ± ± ±
5.6 8.5 9.3 9.0
19.9 18.3 27.7 28.1
± 7.7 ± 10.9 ±9.9 ± 10.4
23.6 ± 10.6
11, n = 12) to 20.5 (s.d. = 48, n = 11) in Porsgrunn and from 25.7 (s.d. = 10.7, n = 22) to 31.3 (s.d. = 10.2, n = 19) in Skien. The children from Porsgrunn with a DFS score of 10 or less (8.3 ±8.3, n = 18) were compared Table 3. The distribution of the mean ( ± s.d.) number of decayed and filled surfaces, DFS, among 14-year-old children according to background characteristics
Mean DFS ± s.d.
Total Town
= 178
Porsgrunn ;; = Skien n= Sex Girls • ;z = Boys n = Soeial elass Low ji = Middle-f-high n= Years oj re.sidetice 5 or less n= 6 or more n= Number oj dentists 1 n= 2 7! = 3 n= Toothbrustiing, teetinique Roll (R) n= Scrubb (S) n= Combination (R-FS) n= Toothbrushing jrequeney Once daily n = Twice daily n= More than twice n= Use oj jluorides at home F-dentifrices jj = No F-vehicle n =
Between sum of square/ total sum of square
23.6± 10.6
88 90
19.3 ± 9.2 27.9 ±10.2
0.17
99 79
23.6 ± 9.6 23.6 ±11.7
0.00
123 55
23.9 ±10.2 22.8 ±11.4
0.02
23 155
27.2 ± 9.6 23.1 ± 10.6
0.02
22 75 81
11.7 ± 8.3 22.1 ±10.2 26.7 ±10.5
0.07
73 42 63
26.5 ±10.8 21.5 ±10.5 21.7 ± 9.7
0.05
34 124 20
22.5 ±10.0 23.4 ±10.6 26.0 ±10.9
0.01
156 22
23.6 ±10.4 24.0 ± 8.8
0.03
204
BiRKELAND AND JoRKJEND
Table 4. The distribution of the mean DFS ( ±s.d.) among children in Porsgrunn and Skien according to three background characteristics Town
Years oj residence 5 or less 6 or more Number oj dentists perjorming treatments n =1
Toothbrushing technique Roll (R) Scrubh (S) Combination (R + S)
Porsgrunn 19.3 ± 9.2 {n
Skien 27.9 ± 10.2 {n = 90)
24.3 18.3
± 9.2 ± 8.8
(n = 14) (« = 74)
31.7 27.5
8.2 ± 10.3 ±
{n = 9) [n = 81)
16.4 ± 8.1 19.8 ± 9.5 20.3 ± 8.9
(n = 17) (n = 48) {n = 23)
22.2 ± 7.2 26.1 ± 10.1 29.2 ± 10.1
{n = 5) {n = 27) {n = 58)
19.5 ± 8.6 17.7 ± 9.3 20.1 ± 9.2
{n =19) (n = 27) {n = 42)
28.9 ± 10.4 28.3 ± 9.1 24.9 ± 9.8
{n = 54) [n = 15) {n = 21)
Girls in both towns had a lower number of Plaque Index scores of 2 than boys (Table 5 ) . Gingival Index scores of 0 and of 3 constituted only fractions of the recordings (Table 6 ) . Between girls and boys there were no differences in the number of the Gingival Index scores. Effect of background characteristics - The predictors sex, social class, number of dentists having performed previous treatments, toothbrushing technique, and toothbrushing frequency had a slight
explanatory power on the number of Plaque Index scores of 2 (Table 7 ) . Differences in the number of Gingival Index scores of 2 were partly explained by the toothbrushing frequency and the use of fluorides at home (Table 7 ). The children with from 0 to 10 or from 31 to 48 instances of Plaque Index seores of 2 were compared. The children from Skien constituted 59 % and 58 % of these subsamples, 51 % in the entire material. Girls were most frequent among children with few scores of 2 (Table 8, x" = 19.6, d.f. = 1). Subjects from the lowest social class tended to be more frequent among children with a high number of 2 scores (z^ = 3.5, d.f. = 1). Ghildren found to have between 31 and 48 Plaque Index scores of 2 had the highest number of Gingival Index scores of 2.
Table 5. The mean ( ± s.d.) number of the Plaque Index scores 0-3 among 14-year-old children participating in preventive programs with fortnightly fluoride (10 ml 0.2 % NaF) mouth rinsing (Porsgrunn) or 4-5 yearly toothbrushings with a fluoride solution (0.5 % NaF - Skien)
Table 6. The mean ( ± s.d.) number of Gingival Index scores of 0-3 among 14-year-old children participating in preventive programs with fortnightly fluoride (10 ml 0.2 % NaF) mouth rinsing (Porsgrunn) or 4-5 yearly toothbrushings with a fluoride solution (0.5 % NaF - Skien)
with participants from Skien with DFS of 40 or more (43.8 ± 2.9, n = 15). Social class had no marked explanatory power in this subsample (26.4 ± 18.7, n = 22 for the low social class vs. 20.5 ± 18.4, n = 11, mean for n = 3 3 : 24.4 ± 18.1). PLAQUE AND GINGIVITIS
Gingival Index score
Plaque Index score Towtifsex
7 ownjsex Porsgrunn Girls (n = Boys {n = Skien Girls (n = Boys {n =
0
1
2
52) 36)
15 + 10 9± 7
15 ±5 14±7
18+12 23 ±12
0.3 ±1.3 1.4±3.6
47) 43)
]5± 9
18±7 16±7
15 + 12 24±12
0.3+1.4 1.1±2.5
7±
8
0
3
Porsgrunn Girls (n = Boys {n = Skien Girls (n = Boys (n =
1
2
3
52) 36)
0. 8 ±3.0
31 ± 9 28 ±10
16± 9 0. 1 ± 0.7 19± 10 0.3±1.1
47) 43)
1. 5 ±5.5 30 ± 9 0. 7 ±4.7 31 ± 8
16± 8 0. l±0.3 16± 8 0. l±0.5
0
Two caries preventive programs 205 Table 7. The distribution of the mean number of Plaque and Gingival Index scores of 2 among 14-year-old children according to background characteristics. (BSS/TSS = Between sum of square/total sum of square) Plaque score 2 X ±'. i.d. '
Gingival score 2 X ± S;.d.
n = 178
BSS/ 19.2 ±12.4 TSS
16.5 ± 9.2
Skien
n = 88 ri = 90
19.8±11.8 !8.6±12.9 (0.00)
16.9 ± 10.0 16.0 ± 8.3
Sex Girls
n = 99
16.2 ±12.0 22.8 ±12.0 (0.07)
15.6± 9.0 17.5± 9.3
Total Town Porsgrunn
Boys tl — 79 Social class Low n = 123
16.5± 11.8 20.5 ± 12.6
16.7 ± 9.3 15.8 ± 9.0
18.0 ± 8.6 19.3 ± 12.9 (0.00)
16.3± 7.9 16.5 ± 9.3
15.9 ± 10.0 17.9 ±12.4 (0.02) 21.2±12.6
17.3 ± 11.3
19.7± 11.1 24.3 ± 11.9 (0.05)
17.0 ± 8.9 17.2± 9.7
15.4+ 11.1
15.4± 9.0
15.1 ± 11.6 18.1 ±12.1 (0.05)
15.9 ± 7.6 17.1 ± 9.7
16.5±13.3
13.8±:7.6
F-dentifrices + F-rinse n = 156 No F-vehicle
18.8 ±12.3
16.1 ± 9.0
22
21.7±12.7
Middle + high n = 55 Years oj residenci 5 or less n ~ 23 6 or more n = 155 Number oj dentists i'.r-n = 22 2 n ~ 75 3
n = 81
Toothbrushing techniques Roll (R) n = 73 Scrubb (S) n = 42
(0.02)
16.3± 16.4±
9.3 8.4
frequent in these subsamples. This finding strengthened the belief that there were marked variations in the oral hygiene of the children with supervised brushing. Children reporting using either the Roll or Scrubb teehnique tended to have a higher number of Plaque Scores of 2 than children using the combination of these techniques (Table 7). Regular attention as with fortnightly mouthrinsing has been assumed to motivate toward improved oral hygiene and gingival conditions"". However, weekly supervised toothbrushing has been found to have no beneficial effect on the oral hygiene and the gingival conditions compared to weekly rinsing". The present findings indicate that supervised brushing 4-5 times yearly had no better motivational effeets than fortnightly rinsing. CARIES The present radiographic examination causes an Table 8. The mean number of Gingival Index scores of 2 among 14-year-old children with less than 11 and more than 30 Plaque Index scores of 2. Maximum number of scores = 48 Number of Plaque Index scores of 2 0-10 31-48
Combination (R + S) 63
Toothbrushing frequeney Once daily n = 34 Twice daily n = 124 More than twice n = 20 Use oj jluorides at home
tl
=
(0.03)
19.1 ± 9.8
DISCUSSION PLAQUE AND GINGIVITIS All children in the present study had gingivitis and no variations in gingival conditions eould be ascribed to the preventive programs. Sex and toothbrushing habits explained most of the variances in the oral hygiene. The improved condition in girls was especially marked when children with the lowest and highest number of Plaque Index scores of 2 were compared. The children from Skien were most
Number of Gingival Index scores of 2 n = 54: n = 38:
11.9 ±7.2 Towti Porsgrunn Skien Sex Girls Boys Soeiat ctass Low Middle + high Toothbrushing techniques Roll (R) n= Scrubb (S) n= Gombination (R + S) n= Toothbrushing jrequeney Once daily Twice daily More than twice n=
22.4 ±9.2
22 32
11.7 ±8.2 « = 1 6 27.3 ± 9.7 12.0 ±6.4 71 = 22 19.0 ± 6.9
42 12
12.1±7.6 11.2±5.5
n = 12 21.4± 7.4 « = 26 22.9± 9.8
34 20
12.6±8.0 10.7±5.3
ti = 31 21.8± 8.6 n= 7 25.4±10.9
20 10
13.5 ±6.0 9.7±5.8
n = 17 20.1 ± 8.1 ?i = 15 23.6± 10.1
24
11.8±6.9
n= 6 26.3 ± 7.8
4 42
11.0±6.3 11.8 ±6.9
n = 1 2 18.4± 6.5 « = 22 25.7 ± 9.8
8
12.6 + 8.6
» = 4 16.5± 2.6
206
BiRKELAND AND JoRKJEND
100 80 MAXILLA 60
40
20
- 1=
= 2 =
—4 =
= 5 =
=6 =
:7
= 5 =
= 6=
--7
20
40 MANDIBLE
60 80 L
1 Fig. 2. Percentage of decayed and filled proximal surfaces among 14-year-old children participating in caries preventive programs with fortnightly fluoride (0.2 % NaF) mouth rinsing (hatched area) or toothbrushing with fluoride (0.5 % NaF) solutions 4-5 times per year (total area). Radiographic diagnosis. The mandibular incisors and the canines were not recorded. Each bar represents a tooth. Right side of bar gives data for distal surface, left side mesial surface.
underestimation, especially in subjects with high caries prevalence. An advantage of this method, however, is that it permits objective comparison in future studies'^. Comparison - Judging from the following considerations, the different earies experience of the children in the two towns is most likely related to the difference in the preventive programs: 1. The earies experiences eould not be ascribed to the predietors sex, soeial class, and use of fluoride at home. These variables had a similar distribution among the children in the two towns. The explanatory power of social class was still moderate when subjeets from Porsgrunn with the lowe.st earies experience were compared with those from Skien with the highest prevalenee. Aeeording to Scandinavian studies, certain factors in the home environments rather than the socioeconomic situa-
tion could be related to the caries experience of 14year-old children^'''*. 2. The different caries experiences in these towns were still evident when the dentists who performed the last treatments were introduced as predictor. The caries prevalences of the children may therefore hardly be eaused by different attitudes to restorative and preventive dentistry among the dentists in the towns. 3. There were different amounts of caries, but the distribution on the various proximal tooth surfaces was similar in both groups of children (Fig. 2). 4. There was a tendency toward lower caries prevalence among children who had been living in these towns for 6 years or more. This tendency was evident in both towns (Table 4) and verifies the effectiveness of the programs. On the other hand, the present caries experiences probably reflect the maximum benefits obtainable using the present programs in these populations. Reasons for benefits — A substantial caries reduction was found in children from Porsgrunn after the introduction of the caries preventive program^ The caries prevalence among children in the two towns may have been at the same level at the initiation of the preventive programs. This view is strengthened by the finding that 15 surfaces had to be filled in 14-year-old children in both towns at the introduction of the programs. Furthermore, no special demographic or social alterations have taken plaee in either of these towns during the past 10 years. The signifieantly different caries experience of the children in Porsgrunn and Skien is probably ascribable to the fluoride applications. Weekly or fortnightly fluoride mouth rinsings seem to give greater benefits'^''^''°'^'' than supervised toothbrushing with fluoride solutions 4-6 times per year"*'"'''•"'' ^\ The frequency of the fluoride applications rather than the fluoride ion concentration seems important''^ This view is in agreement with the assumed mode of action of the fluoride ions'* and the lack of a lasting anticaries effect when fluoride applications were interrupted"". Fluoride-containing dentifrices may have reduced the caries prevalence. This predictor, however, had the same distribution in both towns. The high proportion reporting to use fluoride at home exceeded previous findings in adult Norwegians^ This may be due to motivation of the children and/or overreporting.
Two caries preventive programs 207 A very low caries incidence has been found in children with proper oral hygiene^'". The predictor amount of plaque, however, had no ability to explain the caries experiences between or within the two towns. The different caries experience of the children with mouth rinsing and supervised toothbrushing is most likely related to the frequeneies of the fluoride applications rather than the rinsing and brushing
12. HoLLENDER, L. & KocH, G.: Roentgenographic partial recording of caries in assessment of effect of prophylactic measures. Odontot. Revy 1969: 20: 267-282.
per se.
15.
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E . : Supeivised
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tooth
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3. BERGGREN, H . & WELANDER, E . : The caries-inhibiting
effect of sodium ferric and zirconium fluorides. A comparative study on school children using supervised brushing as the mode of application. Acta Odontol. Scand. 1964: 22: 401-413. 4. BiRKELAND, J. M.: In vitro study on the mechanisms of . action of fluoride in low concentrations. Caries Res. 1975: 9; 110-118. 5. BiRKELAND, J. M. & HELOE, L . A.: Use of fluorides and the learning of interdental cleaning. The dissemination of preventive dental health behavior among adult Norwegians. Community Dent. Oral Epidemiol. 1974: 2: '" 66-69. 6. BiRKELAND, J. M. &. JoRKjEND, L.: A new approach to the evaluation of Plaque Index scores. / . Periodontal Res. 1973: 8; 284-289. 7. BiRKELAND, J. M., JoRKjEND, L. & BROCH, L . : An approach to objective assessment of caries prophylactic •i measures in a dental health program. Community Dent. Oral Epidemiol. 1975: 5; in press. 8. BiRKELAND, J. M., JORKJEND, L. & FEHR, F . R . V. D.: The influence of fluoride mouth rinsing on the incidence of gingivitis in Norwegian children. Community Dent. Oral Epidemiot. 1973: / ; 17-21. 9. BuLLEN, D. C. T., McCoMDiE, F. & HOLE, L. W . : Twoyear effect of supervised toothbrushing with an acidulated fluoride-phosphate solution. / . Can. Dent. Assoe. ' 1966: 32: 89-93. 10. FoRSMAN, B. 1965: Effekten av munskjolningar med natriumfluoiidlosning vid skolar i Vaxjo. Sver. Tandtaek. Foerb. Tidn. 1965: 57: 705-709. 11. HEIEETZ, S. B., DRISCOLL, W . S. & CREIGIITON, W . E . :
The effect on dental caries of weekly rinsing with a neutral sodium fluoride or an acidulated phosphatefluoride mouthwash. / . Am. Dent. Assoc. 1973: 87; 364-368.
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19. LINDHE, J. & AXELSSON, P.: The effect of controlled
oral hygiene and topical fluoride application on caries and gingivitis in Swedish schoolchildren. Community Dent. Oral Epidemiol. 1973: / ; 9-16. 20. LINDHE, J., KOCH, G . & MANSSON, U . : The effect of
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supervised oral hygiene on the gingiva of children. Effect of mouth rinsings. / . Periodontal Res. 1966: 1: 268-275. LOE, H . & SILNESS, J.: Periodontal disease in pregnancy. I. Prevalenee and severity. Acta Odontol. Seand. 1963: 21: 533-551. MARTHALER, T . M . : Reduction of caries, gingivitis and calculus after eight years of preventive measures - Obseivations iu seven communities. Hetv. Odontot. Acta 1972: 16: 69-83. MARTHALER, T . M . : Improved oral health of schoolchildren of 16 communities after 8 years of prevention. I. Combining DMF data from the communities. Hetv. Odontot. Acta 1974: 18: 119-142. SILNESS, J. & LOE, H . : Periodontal disease in pregnancy. II. Correlation between oral hygiene and periodontal condition. Acta Odontol. Scand. 1964: 22: 121-135. ToRELL, P. & ERICSSON, Y . : Two-year clinical tests with different methods of local caries-preventive fluorine application in Swedish school-children. Aeta Odontot. Scand. 1965: 23: 287-322.
Address: Dental Institute oj Experimental Univer.nty oj Oslo Blindern Osto 3 Norway
Researeh
*
