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A combined approach to preventing dental caries in schoolchildren: caries reductions after one year
A p ro to ty p e s c h o o l-b a s e d p re v e n tiv e d e n tis try p ro g ra m is d e s c rib e d te s tin g th e c o m b in e d e ffe c ts o f in g e s tio n o f flu o rid a te d w a te r, th e to p ic a l a p p lic a tio n o f a c id u la te d p h o s p h a te flu o r id e gel, th e use o f p it a nd fis s u re s e a la n ts, p a rtic ip a tio n in d e n ta l h e a lth e d u c a tio n p ro g ra m s , and th e e a rly d e te c tio n o f c a rie s and th e p ro v is io n o f re s to ra tiv e care. A fte r o n e year, o c c lu s a l s u rfa c e s o f p e rm a n e n t te e th in c h ild re n in th e tre a tm e n t g ro u p s h o w e d an a ve ra g e re d u c tio n in c a rie s o f 84% , c o n tra s te d to th o s e in c h ild re n in a c o m p a ris o n g ro u p .
A combined approach to preventing dental caries in schoolchildren: caries reductions after one year
R o b e rt A. B a g ra m ia n , R ic h a rd C. G ra v e s , M o h a n d a s B h at,
DDS, DrPH
DDS, DrPH
MDS, DrPH, Ann Arbor, M ich ^® :
Because of the extremely high prevalence of dental disease and because dental caries and per iodontal disease are largely preventable, in creased emphasis on prevention has been the theme of the dental profession in the past few years. Practical methods of reducing dental car ies, which may be employed in the routine gen eral practice of dentistry, have been developed. Each of the individual preventive methods of water fluoridation,1 topical fluorides,2 health education,3 occlusal sealants,4 and restorative care5 has been studied and reported singly and in some limited combinations. One study, how ever, has reported the combined effects of pre ventive methods to reduce dental caries. The Askov dental demonstration,6 conducted be tween 1948 and 1958, tested the combined car ies-preventive benefits of several procedures practiced during that period and included the application of fluoride topically, supervised daily toothbrushing, dental health education, restric tion of dietary carbohydrates, and provision of restorative care. At the end of ten years, the study showed reductions of 34% in DMFT in 1014 ■ JADA, Vol. 93, November 1976
children ages 6 to 12 years and 14% in children ages 13 to 17 years. The DMFS reductions were 43% for the 6 to 12 year olds and 16% for those ages 13 to 17 years. The children in the study, however, were not consuming fluoridated water, and sealants were not available. This paper describes a prototype preventive dentistry program being conducted for school children in a medium income, racially mixed pop ulation in Ypsilanti, Mich, and the results ob tained after one year. The program is a demon stration project to determine the caries-preven tive benefit provided by a combination of five preventive and therapeutic measures.
D e s c r ip tio n
o f d e m o n s tr a tio n
p ro je c t
Ypsilanti has a population of about 30,000 and is located in a highly populated urban area of south eastern Michigan. Approximately 30% of the children are nonwhite. Many of the families live in low-middle socioeconomic areas and have lim ited access to dental care. The levels of need for
dental care are relatively high. The demonstration project was initiated in early 1973 and designed to continue for four years. All children in the first and sixth grades enrolled in 18 schools in the school districts of Ypsilanti and Willow Run were invited to parti cipate in the program; 1,200 children or about 70% of all the children in these grades received paren tal permission to participate. The sample was stratified by grade and school and then two groups were selected randomly to be treatment and comparison groups. In this way, equal num bers of children were represented at each of 18 schools. First and sixth graders were selected to max imize the potential of the preventive procedures on the large number of newly erupted and erupt ing permanent teeth in children of these ages. These teeth are the first molars in first graders, and bicuspids and second molars in sixth grad ers. Children in the treatment group are ex posed to five preventive and therapeutic meas ures. —The ingestion of optimally fluoridated drink ing water. (Ypsilanti has been fluoridated since 1964 with 1.0 ppm of fluoride.) —An oral hygiene education program in class rooms, including supervised toothbrushing and flossing, and the use of disclosing tablets, for 32 weeks a year, and dietary counseling. —Dental examinations, prophylaxis, and the application of acidulated phosphate fluoride gel (1.23%) applied in trays for four minutes, every six months. —The application of a pit and fissure sealant (Nuva-Seal, Buonocore method) to the occlusal surfaces of all sound teeth as well as newly er upted teeth in which the occlusal surface had penetrated the gingival tissue. Sealant condition is assessed at six-month intervals by the epidem iologists. Sealants are applied to newly erupted teeth and those teeth that have lost sealant.
—The provision of all necessary restorative care. Posterior bitewing radiographs are taken annually for all children and are used for assess ments as well as clinical treatment. Children in the comparison group also con sume fluoridated water. In addition, it was de cided to provide the oral hygiene education pro gram for all children, to minimize logistical prob lems for teachers, to maintain maximum rapport with them, and to provide some preventive ser vices to those students in the comparison group in appreciation for their continued participation in the project. Table 1 shows the essential differ ences between the treatment and the compari son groups. All clinical assessments are conducted by two trained epidemiologists. Actual clinical treat ment is provided by staff clinical dentists and assistants. Children in the treatment group re ceive biannually a prophylaxis, sealant applica tion, topical fluoride, and restorative care. A unique feature of the project is that all nec essary clinical procedures are carried out at each school, with the use of two mobile dental vans. The vans, each staffed by a dentist and two cer tified dental assistants, twice a year, regularly make the rounds at each of the 18 schools at which the project is being conducted. Each van is fully equipped with two operatories; each has an X-ray unit. The vans are self-propelled and can be operated either with a 220-v shore line or independently with their own generators. This arrangement not only saves time in terms of school hours lost by students, but also saves the expense of transportation costs and broken ap pointments if children were to be transported to stationary dental facilities. The oral hygiene program is directed by a den tal hygienist who has a background in education. The program in dental health education is pri marily designed for the elementary grades, first and sixth. The classroom teachers were trained
Table 1 ■ Essential differences and similarities between the treatment a n d com parison groups, preventive dentistry project, Ypsilanti, Mich, 1972-1976. Treatment group
Comparison group
1. Fluoridated drinking water (1.0 ppm) 2. Oral hygiene education program In school Daily supervised brushing & flossing (32 weeks each year) Dietary counseling 3. Dental examinations (posterior bitewing radiographs once a year) Prophylaxis and topical application of APF gel (1.23%) every six months 4. Application of sealant to posterior teeth. (Sealants lost were reapplied every six months) 5. Provision of all necessary restorative care
1. Fluoridated drinking water (1.0 ppm) 2. Oral hygiene education program in school Daily supervised brushing & flossing (32 weeks each year) Dietary counseling 3. Dental examinations (posterior bitewing radiographs once a year) Parents notified if lesions found
B agram ian— Graves— Bhat: PREVENTING CARIES IN SCHOOLCHILDREN ■ 1015
in workshops held by the dental health consul tant and the teachers serve as the dental health educators in their classrooms. Additional guid ance and reinforcement was provided through sessions conducted individually with each teach er before the start of the classroom oral hygiene exercises. Each child is issued a toothbrush, dental floss, disclosing tablets, and mirrors; a dry brush technique is followed to remove plaque stained by the disclosing dye. The teacher and the dental health consultant work out an inter disciplinary approach for correlating dental health with other school subjects. Some of the correlated areas are social studies, language, health science, art, reading, handwriting, com position, and spelling. A variety of resources is used for enhancing the instruction including au diovisual aids such as films, filmstrips, and guide books for parents and teachers, as well as the oral hygiene kits. In the present program, in addition to the den tal health consultant, the dentists and dental as sistants working in the mobile dental vans also are available as resource persons to the class room teachers. Annual assessments of the oral health of the children are conducted by two epidemiologists who are carefully trained and calibrated in sur vey methods. These indexes are used in collect ing data: DMF7 surfaces and teeth, Russell’s periodontal index,8 and the simplified oral hy giene index.9 Examination methods are highly standardized. Criteria used to assess dental car ies are those accepted at the 1968 ADA Confer ence on the Clinical Testing of Caridstatic Agents.10 Posterior bitewing radiographs also are taken. Although the presence of sealant iden tifies a treatment group subject, care is taken to reduce bias. During an assessment process, rec ords of previous examinations are not available to the examiners. The oral conditions are as sessed in this sequence: plaque, calculus, gin gival status, DMF surfaces and teeth. Radio graphs are interpreted and charted on a separate form without benefit of the results of the clinical examination. Radiographic findings are then added to the clinical data.
Table 2 ■ Baseline and first-year increment for DMFT in first graders, Ypsiianti, Mich, 1973-1974.
Group Treatment Comparison t statistic
N 290 301
Baseline exam Mean SE 0.2897 0.0460 0.2857 0.0453 0.0625
'Significant at P<0.01.
Table 3 ■ Baseline and first-year increment for DMFS in first graders, Ypsiianti, Mich, 1973-1 974 .
Group Treatment Comparison t statistic
N 290 302
Baseline exam Mean SE 0.3828 0.0655 0.3654 0.0626 0.1923
Group Treatment Comparison t statistic
N 290 301
'Significant at P<0.01. 1016 ■ JADA, Vol. 93, November 1976
Increment from baseline to 1 yr Mean SE 0.2207 0.0466 0.8439 0.0824 6.4984'
'Significant at P<0.01.
Caries increment data for one year Of the 1,200 children present at the baseline, 1,082 were examined at the end of one year; 118 children were lost because of moves or transfers out of school district. Analysis of caries incre ment data for the permanent teeth after the first year indicates a high degree of success for the treatment group as opposed to the comparison group. At the baseline examination, there was virtually no difference in mean DMFT scores in first graders in the two groups (Table 2); this indicates initial comparability in caries exper ience. At the end of one year, however, the com parison group showed a 3Vi-fold increase in the DMFT increment over that for the treatment group; this is statistically significant at the 1% level. Nearly a fourfold increase in the DMFS increment was found for the comparison group over that for the treatment group and this differ ence is also significant (P<0.01) as shown in Table 3. An analysis of the caries increment data by surface type in first graders showed a small caries increment in buccolingual surfaces, which is greater for the comparison group than for the treatment group (Table 4). Mesiodistal surfaces of the permanent teeth showed essentially no caries activity in either group. The increment in occlusal caries in the comparison group, how-
Table 4 ■ First-year caries increment by surface type in first graders, Ypsiianti, Mich, 1973-1974. Buccolingual increment Mean SE 0.1483 0.0325 0.2492 0.0400 1.9441
Increment from baseline to 1 yr Mean SE 0.1793 0.0340 0.6312 0.0584 6.591*
Mesiodistal increment Mean SE 0.0034 0.0091 0.0066 0.0066 0.2270
Occlusal increment Mean SE 0.0690 0.0231 0.5880 0.0579 8.2120'
1.00 0.90 |
0.80
c
0.70
J
0.60 0.50 0.40 0.30
0.20 0.10
0.00 DMFT
DMFS
O c c lu s a l
Fig 1 ■ First-year caries increment in permanent teeth of first graders, Ypsilanti, Mich, 1973-1974.
Table 5 ■ B aseline and first-year in c re m e n t for D M F T in sixth graders, Y psilanti, M ich, 1973-1974.
Group Treatment Comparison t statistic
N 247 244
Baseline exam Mean SE 3.3239 0.1553 3.3156 0.1629 0.0591
Increment from baseline to 1 yr Mean SE 0.0688 0.0612 1.0574 0.1061 8.1033’
’ Significant at P<0.01.
Table 6 ■ B aseline and first-year in c re m e n t fo r D M F S in sixth grad ers, Y psilanti, M ic h , 1973-1974.
Group Treatment Comparison t statistic
N 247 244
Baseline exam Mean SE 5.6073 0.3286 5.6762 0.3281 0.1484
Increment from baseline to 1 yr Mean SE 0.5020 0.1333 1.3115 0.1787 3.6398*
’ Significant at P<0.01
ever, is more than eight times that seen for the treatment group (PCO.Ol). The significant differ ences in the two groups of first graders are illus trated graphically in Figure 1. DMFT and DMFS scores for sixth graders (Tables 5 and 6) also show that there were no sig nificant differences between children in the treat ment and comparison groups at the baseline ex amination. At the end of one year the DMFT caries increment for the comparison group was more than 15 times that experienced by the treat ment group (P<0.01). The DMFS caries incre-
Fig 2 ■ First-year caries increment in permanent teeth of sixth graders, Ypsilanti, Mich, 1973-1974.
ment in the comparison group was more than 2Vi times greater than that seen in the treatment group; this was significant (/><0.01), as shown in Table 6. An analysis of the first-year DMFS caries in crement in sixth graders is of interest. The buccolingual caries increment in the treatment group was of somewhat greater magnitude than that seen in the comparison group. This difference, however, was not statistically significant (Table 7). The mesiodistal caries increment, on the other hand, was greater for the comparison group, but the absolute difference was so small as not to be statistically significant. The occlusal caries in crement repeated the patterns seen in the first graders, and the fivefold increase seen in the comparison group over that in the treatment group was statistically significant. The signifi cant differences in the two groups of sixth grad ers are illustrated in Figure 2. In addition to the absolute caries incre ments, percent reductions in caries increments of the treated groups as opposed to those of the
Table 7 ■ First-year caries in cre m e n t by su rface type in sixth graders! Y psilanti, M ic h , 1973-1974.
Group Treatment Comparison t statistic
N 247 244
Buccolingual increment Mean SE 0.2915 0.0665 0.1844 0.0754 1.0677
Mesiodistal increment Mean SE 0.0040 0.0722 0.1352 0.0838 1.1884
Occlusal increment Mean SE 0.2065 0.0467 0.9918 0.1011 8.4714
'Significant at P<0.01. Bagramian— Graves— Bhat: PREVENTING CARIES IN SCHOOLCHILDREN ■ 1017
comparison groups also were computed. These percent reductions in the first graders are 71.6 and 73.8 in mean DMFT and mean DMFS, respec tively. The reduction in mean occlusal caries increment was 88.3%. Similarly, the percent reductions in caries in crement in the sixth graders at the end of one year were computed. These reductions are 93.5 and 61.7 in mean DMFT and DMFS, respectively. The reduction in mean occlusal caries incre ment was 79.2%.
D is c u s s io n
The comparison group in this study is by no means a control group. Ethical considerations require that these children be allowed to con tinue to receive regular dental care from private dentists or from other sources; many children in the comparison group do receive care, including preventive services. Therefore, it may be hy pothesized that if a pure control group could be used as a basis for comparison, it would be pos sible to demonstrate even greater reductions in caries increment than those observed. The reductions in caries in the treatment group took place on the occlusal surfaces nearly ex clusively and would be presumably related to the effects of the sealant. The small caries incre ment observed for all tooth surfaces, except the occlusal surfaces, even for the comparison group, is not surprising because the permanent teeth that are most susceptible to caries in these first and sixth graders had been erupted for such a short time. The first permanent molar in the sixth graders is the only tooth highly susceptible to caries that had been erupted for several years and this tooth in the sixth graders had experi enced considerable carious activity in previous years and thus contributed little to the first-year increment. The typical pattern of relatively early carious activity on fissured surfaces of these teeth and the lag in the development of carious lesions on smooth surfaces produce the results observed. It is expected that with time, as these posterior teeth have been in the oral environ ment for more years, the caries increments on the smooth surfaces will reach greater magni tudes. However, it must be remembered that all children in the project receive the benefits of fluoridation, which may protect smooth sur faces, as well as the oral hygiene education pro gram; thus, any greater benefit achieved in the 1018 ■ JADA, Vol. 93, November 1976
treatment group is related only to three of the five provisions of the program: prophylaxis and fluor ide treatments, sealants, and restorative care. The somewhat greater buccolingual incre ment in the treatment group of the sixth graders is thought to be associated with a significant number of extensive carious lesions on the oc clusal surfaces of first molars, determined at the baseline examination. In the course of restoring these large lesions, it was sometimes necessary to extend the restorations onto buccal or lingual surfaces that had not been scored as carious ini tially. These surfaces were then recorded as re stored at the one-year examination and thus add ed to the increment for the treatment group. Sim ilar lesions confined to the occlusal surface that remained unrestored in the comparison group were still counted as carious on the occlusal sur face only and did not add to the increment for that group. Thus, to some extent, treatment of a backlog of dental needs in one group and not in another group may mask the degree of differ ence between the two groups. Although the percent reductions in caries in crement for permanent teeth in the treatment group after one year are impressive, the absolute reductions in numbers of carious teeth and tooth surfaces are relatively small. Several factors may be related to the low caries increment of the un treated comparison group. The population sel ected for study was at an age in which the perm anent teeth most susceptible to caries were new ly erupted, and many not yet erupted, or erupt ing, and thus, their length of exposure to the oral environment was short. Fluoridation of the water supply greatly reduces the caries increment. The natural lag in the carious process, except for fis sured surfaces, of a few years beyond eruption retards the first-year increment. It is hoped that the oral hygiene program conducted in the schools leads to some reduction in caries, al though whether it does and to what extent may be questioned. In addition, parents of the chil dren in the comparison group were informed of the results of the dental examinations and ad vised to secure dental treatment for their chil dren. Many of them did seek care, including pre ventive services; this also could lower the in crement observed. It is expected that in the sub sequent years of the study greater caries increm ents will be found in the comparison group as more permanent teeth have been present longer and exposed to caries attack and that differences between this group and the treated children will be accentuated.
This research is supported by contract no. NIH-NIDR 72-2410.
S u m m a ry
A prototype school-based dental program is be ing conducted in a low-middle-income, urban area, as a demonstration project to test the com bined effect on dental caries of several preven tive measures. Procedures include ingestion of fluoridated water (1.0 ppm), topical application of acidulated phosphate fluoride, application of a pit and fissure sealant, early detection of caries and restoration of affected teeth, and dental health education (oral hygiene and dietary coun seling program). The four-year project began in early 1973. A group of 1,200 children in the first and sixth grades was randomly separated into a treatment and a comparison group. All children participate in a dental health education program and consume fluoridated water. Dental care is provided on site at 18 schools, with the use of two mobile vans, saving time and expense in school hours lost and transportation costs. A hygienist coordinates the oral hygiene and dietary pro grams in classrooms with the help of teachers trained in workshops. Supervised toothbrushing, flossing, and use of disclosing agents are carried on in the classrooms. First-year caries increment data in permanent teeth indicate a high degree of success. Occlusal surfaces of permanent teeth in children in the treatment group, contrasted to those in children in the comparison group, showed an average re duction in caries of 84%. The encouraging results obtained at the end of one year indicate that a school-based preven tive dentistry program may have great potential for preventing and controlling dental caries in schoolchildren.
This paper is based on a presentation before the annual meet ing of the International Association for Dental Research (Amer ican section), April 5, 1975, New York. The informed consents of all human subjects who participated in the experimental investigation(s) reported or described in this manuscript were obtained after the nature of the procedures and possible discomforts and risks had been fully explained. Dr. Bagramian is professor and chairman of the department of community dentistry, School of Dentistry, University of Mich igan, Ann Arbor, 48104. Dr. Graves is assistant professor in the program in dental public health, School of Public Health, Uni versity of Michigan. Dr. Bhat is research associate in the depart ment of community dentistry, University of Michigan. Address requests for reprints to Dr. Bagramian. 1. McClure, F.J. Water fluoridation, the search and the vic tory. Washington, Govt Print Off, 1970, p 109. 2. Horowitz, H.S., and Heifetz, S.B. The current status of topi cal fluorides in preventive dentistry. JADA 81:166 July 1970. 3. Harris, R. Biology of the children of Hopewood House, Bowral, Australia. 4. Observations of dental carles experience extending over five years (1957-1961). J Dent Res 42:1387 NovDee 1963. 4. Buonocore, M.G. Caries prevention in pits and fissures sealed with an adhesive resin polymerized by ultraviolet light: a two-year study of a single adhesive application. JADA 82:1090 May 1971. 5. Waterman, G.E. The Richmond-Woonsocket studies on dental care services for school children. JADA 52:676 June 1956. 6. Jordan, W.A., and others. The Askov dental demonstration: ADA ten year study of a community dental health program: 19481958. Final report. Northwest Dent 38:445 Nov 1959. 7. Klein, H.; Palmer, C.E.; and Krutson, J.W. Studies on dental caries. I. Dental status and dental needs of elementary school children. Public Health Rep 53:751 May 13, 1938. 8. Russell, A.L. A system of classification and scoring for prevalence surveys of periodontal disease. J Dent Res 35:350 June 1956. 9. Greene, J.C., and Vermillion, J.R. The simplified oral hy giene index. JADA 68:25 Jan 1964. 10. American Dental Association, Council on Dental Research and Council on Dental Therapeutics. Principles for the clinical testing of cariostatic agents. Chicago, American Dental Asso ciation, 1972.
Bagram ian— Graves— Bhat: PREVENTING CARIES IN SCHOOLCHILDREN ■ 1019
A combined approach to preventing dental caries in schoolchildren: caries reductions after one year
R o b e rt A. B a g ra m ia n , R ic h a rd C. G ra v e s , M o h a n d a s B h at,
DDS, DrPH
DDS, DrPH
MDS, DrPH, Ann Arbor, M ich ^® :
Because of the extremely high prevalence of dental disease and because dental caries and per iodontal disease are largely preventable, in creased emphasis on prevention has been the theme of the dental profession in the past few years. Practical methods of reducing dental car ies, which may be employed in the routine gen eral practice of dentistry, have been developed. Each of the individual preventive methods of water fluoridation,1 topical fluorides,2 health education,3 occlusal sealants,4 and restorative care5 has been studied and reported singly and in some limited combinations. One study, how ever, has reported the combined effects of pre ventive methods to reduce dental caries. The Askov dental demonstration,6 conducted be tween 1948 and 1958, tested the combined car ies-preventive benefits of several procedures practiced during that period and included the application of fluoride topically, supervised daily toothbrushing, dental health education, restric tion of dietary carbohydrates, and provision of restorative care. At the end of ten years, the study showed reductions of 34% in DMFT in 1014 ■ JADA, Vol. 93, November 1976
children ages 6 to 12 years and 14% in children ages 13 to 17 years. The DMFS reductions were 43% for the 6 to 12 year olds and 16% for those ages 13 to 17 years. The children in the study, however, were not consuming fluoridated water, and sealants were not available. This paper describes a prototype preventive dentistry program being conducted for school children in a medium income, racially mixed pop ulation in Ypsilanti, Mich, and the results ob tained after one year. The program is a demon stration project to determine the caries-preven tive benefit provided by a combination of five preventive and therapeutic measures.
D e s c r ip tio n
o f d e m o n s tr a tio n
p ro je c t
Ypsilanti has a population of about 30,000 and is located in a highly populated urban area of south eastern Michigan. Approximately 30% of the children are nonwhite. Many of the families live in low-middle socioeconomic areas and have lim ited access to dental care. The levels of need for
dental care are relatively high. The demonstration project was initiated in early 1973 and designed to continue for four years. All children in the first and sixth grades enrolled in 18 schools in the school districts of Ypsilanti and Willow Run were invited to parti cipate in the program; 1,200 children or about 70% of all the children in these grades received paren tal permission to participate. The sample was stratified by grade and school and then two groups were selected randomly to be treatment and comparison groups. In this way, equal num bers of children were represented at each of 18 schools. First and sixth graders were selected to max imize the potential of the preventive procedures on the large number of newly erupted and erupt ing permanent teeth in children of these ages. These teeth are the first molars in first graders, and bicuspids and second molars in sixth grad ers. Children in the treatment group are ex posed to five preventive and therapeutic meas ures. —The ingestion of optimally fluoridated drink ing water. (Ypsilanti has been fluoridated since 1964 with 1.0 ppm of fluoride.) —An oral hygiene education program in class rooms, including supervised toothbrushing and flossing, and the use of disclosing tablets, for 32 weeks a year, and dietary counseling. —Dental examinations, prophylaxis, and the application of acidulated phosphate fluoride gel (1.23%) applied in trays for four minutes, every six months. —The application of a pit and fissure sealant (Nuva-Seal, Buonocore method) to the occlusal surfaces of all sound teeth as well as newly er upted teeth in which the occlusal surface had penetrated the gingival tissue. Sealant condition is assessed at six-month intervals by the epidem iologists. Sealants are applied to newly erupted teeth and those teeth that have lost sealant.
—The provision of all necessary restorative care. Posterior bitewing radiographs are taken annually for all children and are used for assess ments as well as clinical treatment. Children in the comparison group also con sume fluoridated water. In addition, it was de cided to provide the oral hygiene education pro gram for all children, to minimize logistical prob lems for teachers, to maintain maximum rapport with them, and to provide some preventive ser vices to those students in the comparison group in appreciation for their continued participation in the project. Table 1 shows the essential differ ences between the treatment and the compari son groups. All clinical assessments are conducted by two trained epidemiologists. Actual clinical treat ment is provided by staff clinical dentists and assistants. Children in the treatment group re ceive biannually a prophylaxis, sealant applica tion, topical fluoride, and restorative care. A unique feature of the project is that all nec essary clinical procedures are carried out at each school, with the use of two mobile dental vans. The vans, each staffed by a dentist and two cer tified dental assistants, twice a year, regularly make the rounds at each of the 18 schools at which the project is being conducted. Each van is fully equipped with two operatories; each has an X-ray unit. The vans are self-propelled and can be operated either with a 220-v shore line or independently with their own generators. This arrangement not only saves time in terms of school hours lost by students, but also saves the expense of transportation costs and broken ap pointments if children were to be transported to stationary dental facilities. The oral hygiene program is directed by a den tal hygienist who has a background in education. The program in dental health education is pri marily designed for the elementary grades, first and sixth. The classroom teachers were trained
Table 1 ■ Essential differences and similarities between the treatment a n d com parison groups, preventive dentistry project, Ypsilanti, Mich, 1972-1976. Treatment group
Comparison group
1. Fluoridated drinking water (1.0 ppm) 2. Oral hygiene education program In school Daily supervised brushing & flossing (32 weeks each year) Dietary counseling 3. Dental examinations (posterior bitewing radiographs once a year) Prophylaxis and topical application of APF gel (1.23%) every six months 4. Application of sealant to posterior teeth. (Sealants lost were reapplied every six months) 5. Provision of all necessary restorative care
1. Fluoridated drinking water (1.0 ppm) 2. Oral hygiene education program in school Daily supervised brushing & flossing (32 weeks each year) Dietary counseling 3. Dental examinations (posterior bitewing radiographs once a year) Parents notified if lesions found
B agram ian— Graves— Bhat: PREVENTING CARIES IN SCHOOLCHILDREN ■ 1015
in workshops held by the dental health consul tant and the teachers serve as the dental health educators in their classrooms. Additional guid ance and reinforcement was provided through sessions conducted individually with each teach er before the start of the classroom oral hygiene exercises. Each child is issued a toothbrush, dental floss, disclosing tablets, and mirrors; a dry brush technique is followed to remove plaque stained by the disclosing dye. The teacher and the dental health consultant work out an inter disciplinary approach for correlating dental health with other school subjects. Some of the correlated areas are social studies, language, health science, art, reading, handwriting, com position, and spelling. A variety of resources is used for enhancing the instruction including au diovisual aids such as films, filmstrips, and guide books for parents and teachers, as well as the oral hygiene kits. In the present program, in addition to the den tal health consultant, the dentists and dental as sistants working in the mobile dental vans also are available as resource persons to the class room teachers. Annual assessments of the oral health of the children are conducted by two epidemiologists who are carefully trained and calibrated in sur vey methods. These indexes are used in collect ing data: DMF7 surfaces and teeth, Russell’s periodontal index,8 and the simplified oral hy giene index.9 Examination methods are highly standardized. Criteria used to assess dental car ies are those accepted at the 1968 ADA Confer ence on the Clinical Testing of Caridstatic Agents.10 Posterior bitewing radiographs also are taken. Although the presence of sealant iden tifies a treatment group subject, care is taken to reduce bias. During an assessment process, rec ords of previous examinations are not available to the examiners. The oral conditions are as sessed in this sequence: plaque, calculus, gin gival status, DMF surfaces and teeth. Radio graphs are interpreted and charted on a separate form without benefit of the results of the clinical examination. Radiographic findings are then added to the clinical data.
Table 2 ■ Baseline and first-year increment for DMFT in first graders, Ypsiianti, Mich, 1973-1974.
Group Treatment Comparison t statistic
N 290 301
Baseline exam Mean SE 0.2897 0.0460 0.2857 0.0453 0.0625
'Significant at P<0.01.
Table 3 ■ Baseline and first-year increment for DMFS in first graders, Ypsiianti, Mich, 1973-1 974 .
Group Treatment Comparison t statistic
N 290 302
Baseline exam Mean SE 0.3828 0.0655 0.3654 0.0626 0.1923
Group Treatment Comparison t statistic
N 290 301
'Significant at P<0.01. 1016 ■ JADA, Vol. 93, November 1976
Increment from baseline to 1 yr Mean SE 0.2207 0.0466 0.8439 0.0824 6.4984'
'Significant at P<0.01.
Caries increment data for one year Of the 1,200 children present at the baseline, 1,082 were examined at the end of one year; 118 children were lost because of moves or transfers out of school district. Analysis of caries incre ment data for the permanent teeth after the first year indicates a high degree of success for the treatment group as opposed to the comparison group. At the baseline examination, there was virtually no difference in mean DMFT scores in first graders in the two groups (Table 2); this indicates initial comparability in caries exper ience. At the end of one year, however, the com parison group showed a 3Vi-fold increase in the DMFT increment over that for the treatment group; this is statistically significant at the 1% level. Nearly a fourfold increase in the DMFS increment was found for the comparison group over that for the treatment group and this differ ence is also significant (P<0.01) as shown in Table 3. An analysis of the caries increment data by surface type in first graders showed a small caries increment in buccolingual surfaces, which is greater for the comparison group than for the treatment group (Table 4). Mesiodistal surfaces of the permanent teeth showed essentially no caries activity in either group. The increment in occlusal caries in the comparison group, how-
Table 4 ■ First-year caries increment by surface type in first graders, Ypsiianti, Mich, 1973-1974. Buccolingual increment Mean SE 0.1483 0.0325 0.2492 0.0400 1.9441
Increment from baseline to 1 yr Mean SE 0.1793 0.0340 0.6312 0.0584 6.591*
Mesiodistal increment Mean SE 0.0034 0.0091 0.0066 0.0066 0.2270
Occlusal increment Mean SE 0.0690 0.0231 0.5880 0.0579 8.2120'
1.00 0.90 |
0.80
c
0.70
J
0.60 0.50 0.40 0.30
0.20 0.10
0.00 DMFT
DMFS
O c c lu s a l
Fig 1 ■ First-year caries increment in permanent teeth of first graders, Ypsilanti, Mich, 1973-1974.
Table 5 ■ B aseline and first-year in c re m e n t for D M F T in sixth graders, Y psilanti, M ich, 1973-1974.
Group Treatment Comparison t statistic
N 247 244
Baseline exam Mean SE 3.3239 0.1553 3.3156 0.1629 0.0591
Increment from baseline to 1 yr Mean SE 0.0688 0.0612 1.0574 0.1061 8.1033’
’ Significant at P<0.01.
Table 6 ■ B aseline and first-year in c re m e n t fo r D M F S in sixth grad ers, Y psilanti, M ic h , 1973-1974.
Group Treatment Comparison t statistic
N 247 244
Baseline exam Mean SE 5.6073 0.3286 5.6762 0.3281 0.1484
Increment from baseline to 1 yr Mean SE 0.5020 0.1333 1.3115 0.1787 3.6398*
’ Significant at P<0.01
ever, is more than eight times that seen for the treatment group (PCO.Ol). The significant differ ences in the two groups of first graders are illus trated graphically in Figure 1. DMFT and DMFS scores for sixth graders (Tables 5 and 6) also show that there were no sig nificant differences between children in the treat ment and comparison groups at the baseline ex amination. At the end of one year the DMFT caries increment for the comparison group was more than 15 times that experienced by the treat ment group (P<0.01). The DMFS caries incre-
Fig 2 ■ First-year caries increment in permanent teeth of sixth graders, Ypsilanti, Mich, 1973-1974.
ment in the comparison group was more than 2Vi times greater than that seen in the treatment group; this was significant (/><0.01), as shown in Table 6. An analysis of the first-year DMFS caries in crement in sixth graders is of interest. The buccolingual caries increment in the treatment group was of somewhat greater magnitude than that seen in the comparison group. This difference, however, was not statistically significant (Table 7). The mesiodistal caries increment, on the other hand, was greater for the comparison group, but the absolute difference was so small as not to be statistically significant. The occlusal caries in crement repeated the patterns seen in the first graders, and the fivefold increase seen in the comparison group over that in the treatment group was statistically significant. The signifi cant differences in the two groups of sixth grad ers are illustrated in Figure 2. In addition to the absolute caries incre ments, percent reductions in caries increments of the treated groups as opposed to those of the
Table 7 ■ First-year caries in cre m e n t by su rface type in sixth graders! Y psilanti, M ic h , 1973-1974.
Group Treatment Comparison t statistic
N 247 244
Buccolingual increment Mean SE 0.2915 0.0665 0.1844 0.0754 1.0677
Mesiodistal increment Mean SE 0.0040 0.0722 0.1352 0.0838 1.1884
Occlusal increment Mean SE 0.2065 0.0467 0.9918 0.1011 8.4714
'Significant at P<0.01. Bagramian— Graves— Bhat: PREVENTING CARIES IN SCHOOLCHILDREN ■ 1017
comparison groups also were computed. These percent reductions in the first graders are 71.6 and 73.8 in mean DMFT and mean DMFS, respec tively. The reduction in mean occlusal caries increment was 88.3%. Similarly, the percent reductions in caries in crement in the sixth graders at the end of one year were computed. These reductions are 93.5 and 61.7 in mean DMFT and DMFS, respectively. The reduction in mean occlusal caries incre ment was 79.2%.
D is c u s s io n
The comparison group in this study is by no means a control group. Ethical considerations require that these children be allowed to con tinue to receive regular dental care from private dentists or from other sources; many children in the comparison group do receive care, including preventive services. Therefore, it may be hy pothesized that if a pure control group could be used as a basis for comparison, it would be pos sible to demonstrate even greater reductions in caries increment than those observed. The reductions in caries in the treatment group took place on the occlusal surfaces nearly ex clusively and would be presumably related to the effects of the sealant. The small caries incre ment observed for all tooth surfaces, except the occlusal surfaces, even for the comparison group, is not surprising because the permanent teeth that are most susceptible to caries in these first and sixth graders had been erupted for such a short time. The first permanent molar in the sixth graders is the only tooth highly susceptible to caries that had been erupted for several years and this tooth in the sixth graders had experi enced considerable carious activity in previous years and thus contributed little to the first-year increment. The typical pattern of relatively early carious activity on fissured surfaces of these teeth and the lag in the development of carious lesions on smooth surfaces produce the results observed. It is expected that with time, as these posterior teeth have been in the oral environ ment for more years, the caries increments on the smooth surfaces will reach greater magni tudes. However, it must be remembered that all children in the project receive the benefits of fluoridation, which may protect smooth sur faces, as well as the oral hygiene education pro gram; thus, any greater benefit achieved in the 1018 ■ JADA, Vol. 93, November 1976
treatment group is related only to three of the five provisions of the program: prophylaxis and fluor ide treatments, sealants, and restorative care. The somewhat greater buccolingual incre ment in the treatment group of the sixth graders is thought to be associated with a significant number of extensive carious lesions on the oc clusal surfaces of first molars, determined at the baseline examination. In the course of restoring these large lesions, it was sometimes necessary to extend the restorations onto buccal or lingual surfaces that had not been scored as carious ini tially. These surfaces were then recorded as re stored at the one-year examination and thus add ed to the increment for the treatment group. Sim ilar lesions confined to the occlusal surface that remained unrestored in the comparison group were still counted as carious on the occlusal sur face only and did not add to the increment for that group. Thus, to some extent, treatment of a backlog of dental needs in one group and not in another group may mask the degree of differ ence between the two groups. Although the percent reductions in caries in crement for permanent teeth in the treatment group after one year are impressive, the absolute reductions in numbers of carious teeth and tooth surfaces are relatively small. Several factors may be related to the low caries increment of the un treated comparison group. The population sel ected for study was at an age in which the perm anent teeth most susceptible to caries were new ly erupted, and many not yet erupted, or erupt ing, and thus, their length of exposure to the oral environment was short. Fluoridation of the water supply greatly reduces the caries increment. The natural lag in the carious process, except for fis sured surfaces, of a few years beyond eruption retards the first-year increment. It is hoped that the oral hygiene program conducted in the schools leads to some reduction in caries, al though whether it does and to what extent may be questioned. In addition, parents of the chil dren in the comparison group were informed of the results of the dental examinations and ad vised to secure dental treatment for their chil dren. Many of them did seek care, including pre ventive services; this also could lower the in crement observed. It is expected that in the sub sequent years of the study greater caries increm ents will be found in the comparison group as more permanent teeth have been present longer and exposed to caries attack and that differences between this group and the treated children will be accentuated.
This research is supported by contract no. NIH-NIDR 72-2410.
S u m m a ry
A prototype school-based dental program is be ing conducted in a low-middle-income, urban area, as a demonstration project to test the com bined effect on dental caries of several preven tive measures. Procedures include ingestion of fluoridated water (1.0 ppm), topical application of acidulated phosphate fluoride, application of a pit and fissure sealant, early detection of caries and restoration of affected teeth, and dental health education (oral hygiene and dietary coun seling program). The four-year project began in early 1973. A group of 1,200 children in the first and sixth grades was randomly separated into a treatment and a comparison group. All children participate in a dental health education program and consume fluoridated water. Dental care is provided on site at 18 schools, with the use of two mobile vans, saving time and expense in school hours lost and transportation costs. A hygienist coordinates the oral hygiene and dietary pro grams in classrooms with the help of teachers trained in workshops. Supervised toothbrushing, flossing, and use of disclosing agents are carried on in the classrooms. First-year caries increment data in permanent teeth indicate a high degree of success. Occlusal surfaces of permanent teeth in children in the treatment group, contrasted to those in children in the comparison group, showed an average re duction in caries of 84%. The encouraging results obtained at the end of one year indicate that a school-based preven tive dentistry program may have great potential for preventing and controlling dental caries in schoolchildren.
This paper is based on a presentation before the annual meet ing of the International Association for Dental Research (Amer ican section), April 5, 1975, New York. The informed consents of all human subjects who participated in the experimental investigation(s) reported or described in this manuscript were obtained after the nature of the procedures and possible discomforts and risks had been fully explained. Dr. Bagramian is professor and chairman of the department of community dentistry, School of Dentistry, University of Mich igan, Ann Arbor, 48104. Dr. Graves is assistant professor in the program in dental public health, School of Public Health, Uni versity of Michigan. Dr. Bhat is research associate in the depart ment of community dentistry, University of Michigan. Address requests for reprints to Dr. Bagramian. 1. McClure, F.J. Water fluoridation, the search and the vic tory. Washington, Govt Print Off, 1970, p 109. 2. Horowitz, H.S., and Heifetz, S.B. The current status of topi cal fluorides in preventive dentistry. JADA 81:166 July 1970. 3. Harris, R. Biology of the children of Hopewood House, Bowral, Australia. 4. Observations of dental carles experience extending over five years (1957-1961). J Dent Res 42:1387 NovDee 1963. 4. Buonocore, M.G. Caries prevention in pits and fissures sealed with an adhesive resin polymerized by ultraviolet light: a two-year study of a single adhesive application. JADA 82:1090 May 1971. 5. Waterman, G.E. The Richmond-Woonsocket studies on dental care services for school children. JADA 52:676 June 1956. 6. Jordan, W.A., and others. The Askov dental demonstration: ADA ten year study of a community dental health program: 19481958. Final report. Northwest Dent 38:445 Nov 1959. 7. Klein, H.; Palmer, C.E.; and Krutson, J.W. Studies on dental caries. I. Dental status and dental needs of elementary school children. Public Health Rep 53:751 May 13, 1938. 8. Russell, A.L. A system of classification and scoring for prevalence surveys of periodontal disease. J Dent Res 35:350 June 1956. 9. Greene, J.C., and Vermillion, J.R. The simplified oral hy giene index. JADA 68:25 Jan 1964. 10. American Dental Association, Council on Dental Research and Council on Dental Therapeutics. Principles for the clinical testing of cariostatic agents. Chicago, American Dental Asso ciation, 1972.
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