Combined fluoride therapies A 6-year double-blind school-based preventive dentistry study in Inverness, Scotland
Kenneth W, Stephen', Elizabeth J, Kay' and J, ivor Tuilis^ 'University of Giasgow, Giasgow, and Health Board, Inverness, Scotland
Stephen KW, Kay EJ, Tullis JI: Combined Huoride therapies. A 6-year doubleblind school-based preventive dentistry study in Iverness, Scotland, Community Dent Oral Epidemiol 1990; 18: 244-8. Abstract - A 6-yr double-blind study was undertaken to compare the caries inhibiting-elTectiveness of (a) I ingF" tablets (daily at school) plus fortnightly rinsitig at school with 1000 ppmF ; (b) 1 nigF" tablets plus placebo rinsing; and (c) placebo tablets plus 1000 ppmF" rinsing. Participants were aged 4,5 5 yr at outset ofthe trial. At baseline, and annually thereafter, clinical caries and bitewing X-ray examinations were undertaken, hence ethical approval for a negative control was not feasible. Fissure sealant presence was also recorded. Initially, 192 children from predominantly low socio-economic backgrounds were enrolled, and baseline analyses showed no significant differences between groups with respect to primary caries prevalence. After 6 yr, 112 children remained, by which time no significant differences were noted between DMFT and DMI"'S values for those in the active tablet/active rinse group, as compared to those in the placebo tablet/active rinse group. However, in relation to both indices, in pemianent first molars, the effectiveness of the active tablet/placebo rinse regime appeared to be significantly poorer than the placebo tablet/active rinse programme. For the active tablet/active rinse group, the DMFT difference was significantly less than the active tablet/placebo rinse group (37.9%), although for the DMFS difference, significance was not achieved. Similar trends were noted when DMFT and DMFS values for all permanent teeth were considered. The occlusal caries prevalence in permanent first molars followed the DMFT pattern, but differenees between combined tablet/rinsing children and tablet-only children could be ascribed solely to the effectiveness of sealant presence. As F^ rinsing was supervised, the most likely explanation of these results is that children involved with active F " tablet ingestion were either not receiving them, or these formulations were being used in such a manner that no extra benefit was obtained. Further cost-effectiveness studies would therefore seem necessary to determine whether ancillary employment would be justified in terms of increased caries benefit.
Numerous studies have reported the anticaries effects of (luoride tablet usage by children at sehool (1). Compared to home-based F tablet regimes, theoretically, a lower total F " dosage is achieved in school distribution programmes, since tablets are only available each school day. Furthermore, the intake of fluoride in a UK school-based regime does not begin until a child is 4 5 yr old. At this age, any benefit to the primary dentition is liniited, and a comprehensive literature review shows that when fiuoride ingestion is instigated after the fourth birthday of participants, no statistically significant caries reductions in the primary dentition are reported (2 5). In contrast, several studies have produced significant caries reductions (from 23'!/(] to 81%) in the permanent dentitions of children who
commenced fiuoride tablet ingestion at .school age (6-8), However, some authors have reported the use of tablets in similar children with less encouraging results (9, 10). On the other hand, home-based nonsupervised F " supplementation schemes rely heavily upon longterm motivation and compliance of the participant and parent (11), but prolonged school-based programmes may suffer from similar compliance difficulties, as they are solely dependent upon teachers' motivation (8). It is now established that the main dental benefits derived from fiuoride are due to its frequent topical enhancement of early carious lesion remineralisation (12). However, the concentration and type of fiuoride appears to be relatively unimportant. Many plaeebo-controlled studies have shown caries reductions of
Key words: clinicai trial: double-blind: fluorides: rinses: tablets K. W. Stephen, University of Giasgow Dental School, 378 Sauchiehall Street, Giasgow, G2 3JZ, Scotland, UK Accepted for pubiication 12 March 1990
20-40% in the pemianent dentitions of children using fluoride mouthrinses (13). Whilst the systemic role of fluoride is still unclear, the World Flealth Organization (14) has stated that "... if an optimal 'systemic' measure is in operation, the additional use of one 'topical' method will be beneficial," Despite this recommendation, when examining the effectiveness of fiuoride regimes, investigators have tended to study the various methods of lluoride administration separately, although a few authors have reported on the effects of combined topical F ^ programmes (15-18), At the outset ofthe trial reported here only HoROwrrz et al. (19) appeared to have undertaken a study where daily F " tablet distribution at school was combined with a weekly school-based 1000 ppm sodium tluoride
Double-blind fluoride tablet Irinsing study Table I. Number of ehildren participating in eaeh lluoride regimen at baseline and 6 yr later No. of children
School A
B C
Baseline
+6 yr
68 60 64
42 36 41
Material and methods As caries has been shown to be more prevalent amongst children belonging to lo'wer social classes (20), this trial involved three schools which housed children from predominantly low socio-economic groups. Prior to the implementation of the preventive regimes, parents were informed via the Highland Health Board's Chief Administrative Dental Officer (C.A.D.O.), of the content and objectives of the project. As a result, 192 youngsters enrolled and only four children were excluded due to laek of parental permission for involvement. At baseline. Primary I participants (age 4.5-5 yr) were examined at school prior to the study, and then annually for 6 yr, under previously described standardised conditions (21), Overall dmf tooth and surface data were recorded, as were DMFT and DMFS ,scores. For
Table 2. Baseline eombiued clinical and radiog r a p h i c caries seores ibr all subjeets at outset and those remaining in the study for 6 yr
School(s)
.V
dnifl (SD)
Baseline stibjeels 3 .51 (3 .22) A 3 .33 (3 .05) B 3 .36 (? .2t)) C
.V dmfs (SD)
n
9.03 (9.64) 8.62 (10.37) 9.22 (11.38)
68 60 64
9.83 (10.00) 8.86 (11,34) 8.68 (11.00)
42 36
6 vr sub/eel'.V A
B C
3 .74 (3 .34) 3 .31 (3 .26) 3 .41 (3 .18)
developed the necessary ncuro-muscular control to cope with the greater volume (25), The rinsing solution (and its placeRinse bo) were prepared by the Pharmacy DeTablets (lorlnighlly during partment, Highland Health Board. (each school day) school term) in School B, the children received daiI mgF 1000 ppmFly, a I nig fiuoride tablet (Zymalluor), 1 mgF NaCl Placebo administered as noted above, plus a fortPlacebo 1000 ppmFnightly rinse with a 0.2% NaCl placebo fiuid (7 ml in Yr 1 3 , 10 ml in Yr 3 6, Table I). In School C, a daily Zyiiiapermanent first molars (the most cariesprcpared placebo tablet was distributed, prone teeth present in the children's as well as a tbrtnightly rinse with IOOO mouths for a considerable proportion of ppnn F " solution (again, 7 ml in Yr 1-3, the study period) the components of the 10 nil in Yr 4-6). No true negative conDMFS scores were recorded separately •M\A for each surface type. The presence trol, i.e. placebo tablet plus placebo rinse, was employed, as permission lor this reof fissure sealants was also recorded, and gime would have been refused on ethical children were questioned as to their dogrounds as all children were to undergo mestic usage of lluoridc tablets and/or rinses. Fluoridated dentifrices were gen- annual radiographic examination. Furthermore, in all schools, each forterally available throughout the area. Exnight, the children were given a 5-10 min aminations were carried out by one talk on aspects of dental health, ovcrexaminer (K.W.S.), using the criteria of and-above the dental health education BENNII- ('/ al. (22), The examiner's 10% provided by the statf liygicnlst during caries-scoring reproducibility was calculated as per the Test-retest method advorinsing sessions. At these times, the hycated by RUGG-GUNN & Hoi.t.ow.A,Y gienist also reiiitbrced staff motivation as (23). In addition to the annual clinical to the need for regular tablet distribuexamination, bitewing radiographs were tion, although it was deemed unwise to taken by an experienced dental radiogra- appear to pressurise teachers by constant pher using a Philips Oralix 65 kV 7,5 niA probing to determine the rate of tablet machine with 20 mm cone, housed in utilisation. a Highland Health Board Community Following annual data collection, the Dental Service mobile unit. The radio- clinical and radiographic information graphs were then developed and scored was entered on to the Uiii\ersity of Glastor caries by an independent assessor. gow's ICL 2988 mainframe computer Throughout the study, the clinical and and analy.sed by Student's /-test for the radiographic examiners were unaware caries evaluation and 2 x 2 chi-squared which preventive package the children testing tor sealant and tooth surface-rehad received. lated data. The allocation of the preventive regimes was by school, the choice being Results made by the Highland Health Board's C.A.D.O. who alone was aware of the Ofthe 192 children examined at baseline, 6 yr later, due to relocation, 73 children children's treatment regimes throughout had been lost to the study and, as shown the study. In School A, for the 6-yr durain Table 1, the drop-out rate was similar tion of the study, it was requested that the children should receive daily, a 1 mg in all schools. Furthermore, the baseline fiuoride tablet (Zymafiuor; Zyma (UK) clinical and radiographic niodilicd dmft/ Ltd, Cheshire, England) via their teacher, s indices (26) of children remaining in the who was asked to attempt to ensure that study showed no signficant differences the tablets were slowly dissolved in the between pupil groups, as was the case mouth, rather than chewed or swallowed overall at baseline (Table 2). The intra(24). ln addition, for the first 3 yr, the examiner reliability coefficient (r), for children rinsed fortnightly, under super- dmft was 0.994, and for dmfs, 0.993. vision of the one hygienist, with 7 ml of Questionnaire analyses showed that 1000 ppm fluoride solution for 1 niin. In only seven children (four in School C, subsequent years, the rinse volume was two in School B, and one in School .A) increased to 10 ml and the duration to 2 claimed to u.se F tablets at home, while min as, by the age of 8 yr, children have none u.sed rinses, flowevcr, when the Preventive regime
mouthrinse. However, the design of this study was such that no concurrent test or control groups were involved, it being of a sequential cross-sectional comparison nature. It was therefore decided to conduct a 6 yr double-blind school-based active controlled trial to examine the effects of combined lluoride tablet and fluoride mouthwash distribution on caries activity in Invernessian children.
41
N . B . No statistically significant differences between schools.
245
246
SfRPHt-N E'r AL.
baseline dmft and dmfs values of each of these seven subjects were identified, their mean scores were surprisingly high, at 4.14 and 12,43 respectively, as compared to the overall lower mean figures in Table 2. Hence it might be concluded that the accuracy of this questionnaire-derived data could be suspect. Details of fissure sealant presence in permanent first molars in the last 2 yr of the study, are given in Table 3, No sealants were present at baseline. However, 6 yr later, 53% of all first molars were deemed to be sealed in School A, as compared to only 14%. in School B, and 16% in School C (/'
Kenneth W, Stephen', Elizabeth J, Kay' and J, ivor Tuilis^ 'University of Giasgow, Giasgow, and Health Board, Inverness, Scotland
Stephen KW, Kay EJ, Tullis JI: Combined Huoride therapies. A 6-year doubleblind school-based preventive dentistry study in Iverness, Scotland, Community Dent Oral Epidemiol 1990; 18: 244-8. Abstract - A 6-yr double-blind study was undertaken to compare the caries inhibiting-elTectiveness of (a) I ingF" tablets (daily at school) plus fortnightly rinsitig at school with 1000 ppmF ; (b) 1 nigF" tablets plus placebo rinsing; and (c) placebo tablets plus 1000 ppmF" rinsing. Participants were aged 4,5 5 yr at outset ofthe trial. At baseline, and annually thereafter, clinical caries and bitewing X-ray examinations were undertaken, hence ethical approval for a negative control was not feasible. Fissure sealant presence was also recorded. Initially, 192 children from predominantly low socio-economic backgrounds were enrolled, and baseline analyses showed no significant differences between groups with respect to primary caries prevalence. After 6 yr, 112 children remained, by which time no significant differences were noted between DMFT and DMI"'S values for those in the active tablet/active rinse group, as compared to those in the placebo tablet/active rinse group. However, in relation to both indices, in pemianent first molars, the effectiveness of the active tablet/placebo rinse regime appeared to be significantly poorer than the placebo tablet/active rinse programme. For the active tablet/active rinse group, the DMFT difference was significantly less than the active tablet/placebo rinse group (37.9%), although for the DMFS difference, significance was not achieved. Similar trends were noted when DMFT and DMFS values for all permanent teeth were considered. The occlusal caries prevalence in permanent first molars followed the DMFT pattern, but differenees between combined tablet/rinsing children and tablet-only children could be ascribed solely to the effectiveness of sealant presence. As F^ rinsing was supervised, the most likely explanation of these results is that children involved with active F " tablet ingestion were either not receiving them, or these formulations were being used in such a manner that no extra benefit was obtained. Further cost-effectiveness studies would therefore seem necessary to determine whether ancillary employment would be justified in terms of increased caries benefit.
Numerous studies have reported the anticaries effects of (luoride tablet usage by children at sehool (1). Compared to home-based F tablet regimes, theoretically, a lower total F " dosage is achieved in school distribution programmes, since tablets are only available each school day. Furthermore, the intake of fluoride in a UK school-based regime does not begin until a child is 4 5 yr old. At this age, any benefit to the primary dentition is liniited, and a comprehensive literature review shows that when fiuoride ingestion is instigated after the fourth birthday of participants, no statistically significant caries reductions in the primary dentition are reported (2 5). In contrast, several studies have produced significant caries reductions (from 23'!/(] to 81%) in the permanent dentitions of children who
commenced fiuoride tablet ingestion at .school age (6-8), However, some authors have reported the use of tablets in similar children with less encouraging results (9, 10). On the other hand, home-based nonsupervised F " supplementation schemes rely heavily upon longterm motivation and compliance of the participant and parent (11), but prolonged school-based programmes may suffer from similar compliance difficulties, as they are solely dependent upon teachers' motivation (8). It is now established that the main dental benefits derived from fiuoride are due to its frequent topical enhancement of early carious lesion remineralisation (12). However, the concentration and type of fiuoride appears to be relatively unimportant. Many plaeebo-controlled studies have shown caries reductions of
Key words: clinicai trial: double-blind: fluorides: rinses: tablets K. W. Stephen, University of Giasgow Dental School, 378 Sauchiehall Street, Giasgow, G2 3JZ, Scotland, UK Accepted for pubiication 12 March 1990
20-40% in the pemianent dentitions of children using fluoride mouthrinses (13). Whilst the systemic role of fluoride is still unclear, the World Flealth Organization (14) has stated that "... if an optimal 'systemic' measure is in operation, the additional use of one 'topical' method will be beneficial," Despite this recommendation, when examining the effectiveness of fiuoride regimes, investigators have tended to study the various methods of lluoride administration separately, although a few authors have reported on the effects of combined topical F ^ programmes (15-18), At the outset ofthe trial reported here only HoROwrrz et al. (19) appeared to have undertaken a study where daily F " tablet distribution at school was combined with a weekly school-based 1000 ppm sodium tluoride
Double-blind fluoride tablet Irinsing study Table I. Number of ehildren participating in eaeh lluoride regimen at baseline and 6 yr later No. of children
School A
B C
Baseline
+6 yr
68 60 64
42 36 41
Material and methods As caries has been shown to be more prevalent amongst children belonging to lo'wer social classes (20), this trial involved three schools which housed children from predominantly low socio-economic groups. Prior to the implementation of the preventive regimes, parents were informed via the Highland Health Board's Chief Administrative Dental Officer (C.A.D.O.), of the content and objectives of the project. As a result, 192 youngsters enrolled and only four children were excluded due to laek of parental permission for involvement. At baseline. Primary I participants (age 4.5-5 yr) were examined at school prior to the study, and then annually for 6 yr, under previously described standardised conditions (21), Overall dmf tooth and surface data were recorded, as were DMFT and DMFS ,scores. For
Table 2. Baseline eombiued clinical and radiog r a p h i c caries seores ibr all subjeets at outset and those remaining in the study for 6 yr
School(s)
.V
dnifl (SD)
Baseline stibjeels 3 .51 (3 .22) A 3 .33 (3 .05) B 3 .36 (? .2t)) C
.V dmfs (SD)
n
9.03 (9.64) 8.62 (10.37) 9.22 (11.38)
68 60 64
9.83 (10.00) 8.86 (11,34) 8.68 (11.00)
42 36
6 vr sub/eel'.V A
B C
3 .74 (3 .34) 3 .31 (3 .26) 3 .41 (3 .18)
developed the necessary ncuro-muscular control to cope with the greater volume (25), The rinsing solution (and its placeRinse bo) were prepared by the Pharmacy DeTablets (lorlnighlly during partment, Highland Health Board. (each school day) school term) in School B, the children received daiI mgF 1000 ppmFly, a I nig fiuoride tablet (Zymalluor), 1 mgF NaCl Placebo administered as noted above, plus a fortPlacebo 1000 ppmFnightly rinse with a 0.2% NaCl placebo fiuid (7 ml in Yr 1 3 , 10 ml in Yr 3 6, Table I). In School C, a daily Zyiiiapermanent first molars (the most cariesprcpared placebo tablet was distributed, prone teeth present in the children's as well as a tbrtnightly rinse with IOOO mouths for a considerable proportion of ppnn F " solution (again, 7 ml in Yr 1-3, the study period) the components of the 10 nil in Yr 4-6). No true negative conDMFS scores were recorded separately •M\A for each surface type. The presence trol, i.e. placebo tablet plus placebo rinse, was employed, as permission lor this reof fissure sealants was also recorded, and gime would have been refused on ethical children were questioned as to their dogrounds as all children were to undergo mestic usage of lluoridc tablets and/or rinses. Fluoridated dentifrices were gen- annual radiographic examination. Furthermore, in all schools, each forterally available throughout the area. Exnight, the children were given a 5-10 min aminations were carried out by one talk on aspects of dental health, ovcrexaminer (K.W.S.), using the criteria of and-above the dental health education BENNII- ('/ al. (22), The examiner's 10% provided by the statf liygicnlst during caries-scoring reproducibility was calculated as per the Test-retest method advorinsing sessions. At these times, the hycated by RUGG-GUNN & Hoi.t.ow.A,Y gienist also reiiitbrced staff motivation as (23). In addition to the annual clinical to the need for regular tablet distribuexamination, bitewing radiographs were tion, although it was deemed unwise to taken by an experienced dental radiogra- appear to pressurise teachers by constant pher using a Philips Oralix 65 kV 7,5 niA probing to determine the rate of tablet machine with 20 mm cone, housed in utilisation. a Highland Health Board Community Following annual data collection, the Dental Service mobile unit. The radio- clinical and radiographic information graphs were then developed and scored was entered on to the Uiii\ersity of Glastor caries by an independent assessor. gow's ICL 2988 mainframe computer Throughout the study, the clinical and and analy.sed by Student's /-test for the radiographic examiners were unaware caries evaluation and 2 x 2 chi-squared which preventive package the children testing tor sealant and tooth surface-rehad received. lated data. The allocation of the preventive regimes was by school, the choice being Results made by the Highland Health Board's C.A.D.O. who alone was aware of the Ofthe 192 children examined at baseline, 6 yr later, due to relocation, 73 children children's treatment regimes throughout had been lost to the study and, as shown the study. In School A, for the 6-yr durain Table 1, the drop-out rate was similar tion of the study, it was requested that the children should receive daily, a 1 mg in all schools. Furthermore, the baseline fiuoride tablet (Zymafiuor; Zyma (UK) clinical and radiographic niodilicd dmft/ Ltd, Cheshire, England) via their teacher, s indices (26) of children remaining in the who was asked to attempt to ensure that study showed no signficant differences the tablets were slowly dissolved in the between pupil groups, as was the case mouth, rather than chewed or swallowed overall at baseline (Table 2). The intra(24). ln addition, for the first 3 yr, the examiner reliability coefficient (r), for children rinsed fortnightly, under super- dmft was 0.994, and for dmfs, 0.993. vision of the one hygienist, with 7 ml of Questionnaire analyses showed that 1000 ppm fluoride solution for 1 niin. In only seven children (four in School C, subsequent years, the rinse volume was two in School B, and one in School .A) increased to 10 ml and the duration to 2 claimed to u.se F tablets at home, while min as, by the age of 8 yr, children have none u.sed rinses, flowevcr, when the Preventive regime
mouthrinse. However, the design of this study was such that no concurrent test or control groups were involved, it being of a sequential cross-sectional comparison nature. It was therefore decided to conduct a 6 yr double-blind school-based active controlled trial to examine the effects of combined lluoride tablet and fluoride mouthwash distribution on caries activity in Invernessian children.
41
N . B . No statistically significant differences between schools.
245
246
SfRPHt-N E'r AL.
baseline dmft and dmfs values of each of these seven subjects were identified, their mean scores were surprisingly high, at 4.14 and 12,43 respectively, as compared to the overall lower mean figures in Table 2. Hence it might be concluded that the accuracy of this questionnaire-derived data could be suspect. Details of fissure sealant presence in permanent first molars in the last 2 yr of the study, are given in Table 3, No sealants were present at baseline. However, 6 yr later, 53% of all first molars were deemed to be sealed in School A, as compared to only 14%. in School B, and 16% in School C (/'
