ORIGINAL Hedman ARTICLE et al
Dental Hygienists Working in Schools – A Two-year Oral Health Intervention Programme in Swedish Secondary Schools Eva Hedmana/Pia Gabreb/Dowen Birkhedc Purpose: To investigate the possibility of influencing adolescents’ caries incidence, knowledge and attitudes to oral health and tobacco through a school-based oral health intervention programme. Materials and Methods: Four schools in a county in Sweden were randomised to one intervention and one control group. At the intervention schools, two dental hygienists worked 4 h every week for two years. Health education and preventive measures, such as fluoride varnish treatments every 6 months, were performed. The control group had no intervention. The study included a total of 534 participants aged 12–16 years. Outcome variables of the study were 1) caries incidence assessed on bite-wing radiographs and 2) knowledge and attitudes measured through questionnaires. Results: The intervention programme impacted on the incidence of enamel caries, while no effect on dentin caries could be seen. Data from the questionnaires showed that the adolescents considered their teeth as important. Adolescents in the intervention group had better knowledge about oral health and oral hygiene compared to the control group after the two years, but no impact on attitudes toward tobacco could be seen. A majority of the adolescents were positive to the education about oral health and tobacco and they believed that the dental hygienists would help them improve their oral health. Conclusions: Although the effects of the intervention as regards to caries incidence, knowledge and attitudes were limited, the presence of dental hygienists in school was appreciated by the adolescents and seemed to increase their interest in their oral health. Key words: adolescents, caries, fluoride varnish, oral health, prevention Oral Health Prev Dent 2015;13:177-188 doi: 10.3290/j.ohpd.a32132
D
ental caries has decreased considerably among children and adolescents over the last four decades in industrialised countries, mainly due to the widespread use of fluoride toothpaste (Marinho et al, 2003b). However, threats to oral health have a
Dental Hygienist, Department of Preventive Dentisty, Public Dental Health, Uppsala County Council, Uppsala, Sweden; Department of Cariology, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Sweden.
b
Dentist, Department of Preventive Dentisty, Public Dental Health, Uppsala County Council, Uppsala, Sweden; Department of Cariology, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Sweden.
c
Professor, Department of Cariology, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Sweden.
Correspondence: Eva Hedman, Department of Preventive Dentisty, Public Dental Health, Ulleråkersvägen 21, SE- 750 17 Uppsala, Sweden. Tel: +46-18-611-6439, Fax: +46-18-611-6120. Email: [email protected]
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Submitted for publication: 06.11.12; accepted for publication: 14.05.13
been increasing during the same period because of change of life-style factors. The risk factors for oral disease are often the same as those implicated in major general diseases (Petersen, 2008). Thus, a large and frequent sugar intake can cause not only caries, but also overweight and diabetes (Costacurta et al, 2011). Tobacco use is also associated with an increased risk of oral diseases, such as periodontal diseases and mucosal lesions (Papapanou, 1999; Byrappagari et al, 2006; Roosaar et al, 2007). Many young people start using tobacco during adolescence and almost all debuts occur between the ages of 11 and 16 (Galanti et al, 2001; Turner et al, 2004). Adolescence is an important time of life for health promotion and it is known that toothbrushing, smoking, physical activity and dietary habits are established during this period (Kelder et al,
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Four elementary schools, 556 adolescents total
534 adolescents agreed to participate
Did not complete four fluoride varnish treatments: N= 10*
No X-rays at baseline and/or after two years: N=33*
Did not answer the questionaire at baseline and/or after two years: N=29*
Two intervention schools, N=270 Proportion of girls: 45% Proportion of adolescents with immigrant background: 9%
Two control schools, N=264 Proportion of girls: 49% Proportion of adolescents with immigrant background: 7%
- Clinical examination including bite-wing radiographs - Caries risk assessment - Preventive measures according to individual indications
- Clinical examination including bite-wing radiographs - Caries risk assessment - Preventive measures according to individual indications
Questionnaire
Questionnaire
School-based oral health intervention (Table 1)
Two years after baseline examination: Clinical examination including bitewing radiographs
Two years after baseline examination: Clinical examination including bitewing radiographs
No X-rays at baseline and/or after two years: N=37*
Did not answer the questionaire at baseline and/or after two years: N=35*
Questionnaire
Questionnaire
Completed all parts: N=212 According to intention to treat:** N=237 included in caries analysis N=242 included in questionnaire analysis
Completed all parts: N=208 According to intention to treat:** N=227 included in caries analysis N=229 included in questionnaire analysis
*The same individual can appear in more than one drop-out box
**All adolescents who had agreed to participate in the study from the beginning were included in the final analysis.
Fig 1 Flow chart of the study.
1994, Kuusela et al, 1997). Adolescents spend thousands of hours in the school environment, which makes the school a natural arena for health promotion. Studies on oral health promotion programmes at school have shown varying results and it is unclear which type of intervention is the most effective (Kay and Locker, 1998; St Leger, 2001). Systematic reviews stress the use of fluoride and its caries-reducing effects (Marinho et al, 2003a; Marinho et al, 2003b). Despite improved dental health in Sweden, caries is still a problem in many children, in which not using fluoride toothpaste properly, bad oral hygiene and dietary habits play a key role (Fejerskov, 2004). Caries is also related to socioeconomic conditions, such as the educational level of the parents and
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immigrant backgrounds (Skeie et al, 2005). A large proportion of children in Sweden have had some dental caries by the time they are 12–16 years old, especially when approximal enamel caries also is included. Around 10%–15% of children and adolescents have serious problems with caries, a proportion that has remained unchanged over a long period (Bagramian et al, 2009). During the 1980s, when only a small proportion of the children and adolescents were suffering from poor dental health, many Swedish counties changed from a population-oriented approach to an individual high-risk strategy. Such a high-risk strategy involves the identification of individuals at risk for caries, who are then offered individually designed preventive measures (Hausen et al, 2000).
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Table 1 Components of the school-based oral health intervention Intervention components
Description
Parent meetings
At the start of the study in grades 6–9
Population Education about oral health
All participants were offered lessons once each semester for 2 years. Content: toothbrushing with fluoride toothpaste twice per day, the impact of daily habits on oral health, avoiding sugar-containing food and drink, risks of tobacco use Method: student-centered learning, values clarification Aids: books, films, photos, exhibition about sugar in food, tobacco props that shows health risks and financial disadvantages
Fluoride varnish treatments
Every 6 months in grades 6–9
Spontaneous visits
Participants in grades 6–9 were able to attend the school dental clinic on their own initiative
High risk Screening and prophylaxis
Participants at high risk of dental diseases were offered preventive measures and health dialogues at the school clinic
The effectiveness of this high-risk strategy has been questioned since many children with low and moderate risk were also developing new caries (Batchelor and Sheiham, 2002). The most effective way to reduce caries may therefore be to focus on population-based interventions. Programmes carried out in school include all children in a natural way. Moreover, young people with the highest risk for caries have the most to gain from this strategy (Moberg Sköld et al, 2005). The aim of the present investigation was therefore to study the possibility of influencing adolescents’ caries incidence, knowledge and attitudes toward oral health and tobacco use through a school-based oral health intervention programme, carried out by two trained dental hygienists who regularly visited the schools.
MATERIALS AND METHODS Study design An oral health intervention programme was conducted in the county of Uppsala, Sweden. Two intervention and two control schools were included in a longitudinal experimental study (Fig 1). The programme was introduced in August 2009 in grades 6, 7 and 8 of four secondary schools, when the students were 13, 14 and 15 years old, respectively. It ran for 2 years until the students finished grades 7, 8 and 9 (in June 2011). Two dental hygienists, one for each intervention school, imple-
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mented the programme; they were in school 4 hours per week during the semesters. The hygienists worked on oral health education and preventive measures (Table 1) and had been trained to perform education and preventive measures in similar ways in both schools. The effect of the intervention programme was evaluated and caries incidence, knowledge and attitudes to oral health and tobacco use were measured in the study in terms of study outcomes. During the study and at the end of each semester, the methods and contents of the intervention were discussed in meetings with the dental hygienists and one of the authors (EH). No interventions were carried out in the control group, but the effects of caries incidence, knowledge and attitudes were measured in the same way as in the intervention group (Fig 1). The study was approved by the Ethics Committee, Faculty of Medicine, Uppsala University, Sweden. Informed consent was obtained from all participants and their parents/guardians before the study started.
Subjects For practical reasons, the participants could not be randomly selected into test and control groups. Instead, four schools were chosen based on specific inclusion criteria (see below). After the schools had been selected, it was decided by drawing lots which should be the intervention schools and which
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should be control schools. Inclusion criteria were: 1) the school should have a student population of at least 100 students, 2) grades 6–8 should be represented, 3) the school should not be situated in an area with low caries risk and 4) the school must be able to offer a special room for the dental hygienist during a 2-year period. The study design is shown in Fig 1. In accordance with the principles of intention-totreat, all adolescents who had agreed to participate in the study from the beginning were included in the final analysis, assuming that radiographs or questionnaires from baseline and after two years were available (Fig 1). The project was introduced to adolescents, parents and school staff through a letter and meetings in school before the study began.
Education about oral health and tobacco The programme consisted of recurrent education about oral health and tobacco once each semester over a two-year period. The education took place in conjunction with ordinary lessons in Biology and Chemistry, during which the dental hygienist cooperated with the ordinary school teachers. The hygienists were trained in working with an approach called ‘Values Clarification’, a methodology based on educational theories of cooperative, interactive and student-centred learning (O’Dea and Abraham, 2000). The aim was to influence people in groups, their attitudes and behaviour in matters of lifestyle. It was important not to pre-arrange the teaching in detail as the lesson aimed to stimulate communication among the adolescents, dental hygienist and school staff. The focus was on problems that the adolescents themselves had defined as important and on generating an interest in health-promoting behaviours (Flay, 2009; Hedman et al, 2010). The contents of the educational programme and methods and aids used are described in Table 1. The dental hygienist, school teachers and adolescents discussed issues involving oral health, including dietary habits, oral hygiene and tobacco use. Special attention was devoted to the negative oral health consequences of frequent consumption of sugar-containing products and snacks, the importance of toothbrushing twice a day with fluoride toothpaste and the harmful effects of smoking and snuffing tobacco.
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Open clinic in school The dental hygienist had an open clinic for 4 hours each week at school, during which screenings, fluoride varnish treatments and other preventive measures were carried out regularly. Fluoride treatment: All students were offered fluoride varnish treatment every six months. The adolescents arrived at the school clinic in groups of two to three students. If necessary, the teeth were cleaned with a toothbrush and dental floss. Cotton rolls were placed in the vestibulum of the upper and lower jaws and the varnish (Duraphat 22.6 mg F/ml, Colgate; Piscataway, NJ, USA) was applied thinly with a small cotton stick (Quick-Stick, Dentsolv; Saltsjöbo, Sweden). All approximal surfaces, from the distal surface of the canines and to the mesial surfaces of the second molars, were treated. The adolescents were asked not to eat for a few hours and abstain from cleaning their teeth until the following day.
Preventive measures Adolescents in the intervention schools who were identified as at risk of caries were offered individualised preventive measures at the school clinic. They had been identified as high-risk patients by a dentist or dental hygienist at the regular check-up at the public dental clinic. Based on the patient’s individual history, where social, medical and oral conditions were considered, the adolescents were given dietary advice, oral hygiene instructions and fluoride treatments (varnish, rinsing solution, toothpaste) at school. Through dialogue, the hygienist tried to motivate the adolescents to improve their oral health behaviour. Adolescents who did not choose to receive supplemental preventive measures at school were offered the same treatment at the dental clinic. In the control schools, all adolescents who were identified as at risk of caries received the same preventive care at the dental clinic. On their own initiative, the adolescents and school staff could visit the dental hygienist for advice and help; oral-care products (toothbrushes and toothpaste) were for sale at a low cost. She also supported school staff, for instance, by advising which products should be sold in the school cafeteria and participating in various health activities at the school and at parent meetings.
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Caries registration During a clinical examination by the adolescent’s usual dentist or dental hygienist at the public dental clinic, two or four bite-wing radiographs were taken before the study started and were then repeated approximately two years later. All radiographs were assessed using a high resolution LCD screen (Olorin VistaLine VC 1900, Olorin; Kungsbacka, Sweden) and were analysed blindly as described by Gröndahl et al (1977) by one and the same dentist. Before the study began, the dentist’s assessments of radiographs were calibrated with those of another dentist with great experience in caries research (author P.G.). A protocol was designed and data concerning caries risk, date of last previous clinical examination and bite-wing radiographs were collected from the records. The caries status of the approximal surfaces in permanent teeth was registered and, in addition, it was noted if any tooth surface was missing or if caries registration was not possible due to poor quality of the films. All approximal surfaces of permanent premolars and molars were scored as follows (modified from Moberg Sköld et al, 2005): 0 = caries free, 1 = caries lesion in the outer half of the enamel; 2 = caries lesion more than halfway through the enamel without passing the enameldentin junction, 3 = caries lesion extending into dentin, 4 = filled surfaces, 5 = surfaces impossible to score and 6 = teeth not yet erupted. If a tooth surface wase initally caries-free and later developed an enamel or dentin lesion or filling, this was defined as ‘caries incidence’ (0–1–4). All surfaces with caries at baseline and where the caries lesion had a higher value after two years were noted as ‘caries progression’. Preventive fraction (PF), the proportion of lesions that may be prevented, was calculated and expressed as a percentage of the difference of mean caries incidence between control and intervention groups. The dentist responsible for scoring the study results did not know if the patient belonged to the intervention or control group.
Questionnaire Information about adolescents’ knowledge of and attitudes toward oral health and tobacco use was collected through questionnaires at both the start and the end of the study at the intervention and control schools. At the start of the study, it con-
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sisted of 16 structured questions with fixed answers, referred to oral health, dietary habits and tobacco use and was partly based on a questionnaire used in a previous study (Hedman et al, 2006). The questionnaire used in the intervention schools at the end of the study consisted of the same 16 questions, in addition to one question about the intervention programme. The response options were dichotomised into ‘right’ and ‘wrong’ answers.
Statistical analyses A power calculation was made to determine the number of participants in the study. Power was calculated for two variables: 1) expected caries development and 2) expected difference in attitude to oral health and tobacco use, based on the results of studies by Moberg Sköld et al (2005) and Hedman et al (2006). A sample size of 180 in each group was calculated to have 80% power to detect a mean difference of 0.15 in DSa (number of approximal tooth surfaces with dentin lesions). Taking into account that a nonparametric test should be performed, approximately 200 school children in each group were needed. All data were single key entered into a PheedIt database. A logical check of all data was performed with an error rate of 0.02%. Analysis was based on all adolescents included in the study at baseline according to the intention-totreat principles, which means that all the randomised adolescents’ data were used for analysis regardless of whether or not they participated in all interventions. Two hypotheses were tested in the study: 1) no association exists between intervention and caries and 2) no association exists between intervention and knowledge of/attitude toward oral health and tobacco. Dichotomised caries incidence and progression at the end of the study and dichotomised knowledge/attitude at the end of the study were the response variables. The results were expressed as odds ratios (OR) and corresponding 95% confidence intervals (CI) with the associated p-value. The interaction between time and group was tested by using ‘discordant pairs’ for the control and treatment groups in a single table as well as by performing Fisher’s exact test (Hu et al, 1998) and applying a clustered permutation test with 1000 permutations (Stedman et al, 2009). If the outcome of interest is attitude concerning tobacco use, the ‘discordant pairs’ are the children that changed
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attitude concerning tobacco use during the study, i.e. a different outcome at follow-up compared to baseline. In order to evaluate differences in caries incidence and progression between the two groups, the number of surfaces with an incidence and/or caries progression was calculated for each participant. The Mann-Whitney U-test was calculated and a clustered permutation test carried out. Intra-examiner reliability was analysed with Cohen’s kappa coefficient. All statistical analyses were performed with two-sided tests at the 0.05 level of significance.
RESULTS Drop-outs and intra-examiner reliability In total, 556 adolescents from the four schools were invited and 534 agreed to participate in the study. The distribution of individuals between the intervention and control groups was even and no differences between sex or country of birth were observed (Fig 1). Of those 270 subjects at the intervention schools who agreed to participate, 10 did not complete all parts of the intervention. In the caries analysis, 237 and 227 adolescents in the intervention and control groups, respectively, were included. The corresponding number in the analysis of questionnaires was 242 and 229 subjects, respectively (Fig 1). The reasons for not taking part in all parts of the intervention, not having available radiographs or having answered the questionnaire twice were that the adolescents were seeing a private dentist, had moved from the area or refused to participate. The proportions of drop-outs were equal in both groups. The percentage of tooth surfaces for which the quality of the radiographs was inadequate for caries assessment or the tooth had not yet erupted at baseline was 12% in the intervention group and 13% in the control group. After two years, the intervention group exhibited 14% surfaces that did not allow caries assessment and the corresponding figure for the control group was 11%. The intra-examiner reliability was measured by allowing the investigator to repeat the examination of the bite-wing radiographs for 50 participants selected on a random basis. Kappa values for intra-observer agreement for both enamel and manifest caries were 0.87 (Cohen, 1960).
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Caries At baseline, 74% of the participants in the intervention group and 72% in the control group were caries free, defined as no approximal enamel or dentin carious lesions on levels 1+2+3 nor approximal fillings (D1+2+3FSa = 0); approximately 24% in both groups had approximal enamel caries on level 1 and approximal enamel carious lesions more than halfway through the enamel but not passing the enamel-dentin junction (D1+2Sa ≥1). After two years, the number of caries-free individuals had decreased by 5% in the intervention group and by 9% in the control group (Table 2). The prevalence of enamel caries level 1 increased less in the intervention group than in the control group. After two years, the number of individuals who had enamel caries level 1 (D1Sa) had increased by 2% among the individuals in the intervention group as compared with 12% in the control group (p < 0.01, Table 2). Caries prevalence, incidence and progression at baseline and after two years are illustrated in Table 3. There were no differences in caries prevalence when the study began. After two years, the caries incidence was lower, although not statistically significant for the adolescents in the intervention group (p = 0.10). The preventive fraction (PF), measured by incidence of approximal caries as the threshold, was 50% for the intervention group as compared with that of the control group.
Knowledge and attitudes At baseline, the intervention and control groups showed similar distributions with regard to sex, country of birth and tobacco use. A total of 8% of the participants had immigrant backgrounds and the use of tobacco was generally low in the entire population studied (Fig 1, Table 4). Attitudes and knowledge in most areas were favourable both at baseline and at the end of two years (Table 5). The majority of the participants in both groups and on both occasions reported that their teeth were ‘very important’ or ‘rather important’ (question 3). Significantly more adolescents in the intervention group stated that toothbrushing should be carried out twice a day (question 4). There were also more adolescents in the intervention group, although this was not significant (p = 0.067), who knew the positive effects of using fluoridated toothpaste (question 8). Concerning
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Table 2 Proportions and numbers of individuals with approximal caries lesions and fillings in intervention and control groups at baseline and after 2 years Intervention group (n=237)
Control group (n=227)
Baseline % (n)
2 years % (n)
OR (CI)
Baseline % (n)
2 years % (n)
OR (CI)
p-value*
D1Sa ≥ 1
23.2 (55)
24.9 (59)
1.2 (0.7-2.2)
20.7 (47)
33.0 (75)
5.0 (2.2-11)
0.002
D1+2Sa ≥ 1
24.5 (58)
27.8 (66)
1.5 (0.8-2.8)
24.2 (55)
34.4 (78)
3.9 (1.9-9.8)
0.07
D1+2+3Sa ≥ 1
24.9 (59)
28.3 (68)
1.5 (0.8-2.9)
25.1 (57)
34.8 (79)
3.4 (1.6-7.0)
0.09
D1+2+3FSa ≥ 1
26.2 (62)
31.6 (75)
2.0 (1.0-4.1)
27.8 (63)
36.6 (83)
3.5 (1.5-7.4)
0.28
Caries index
*Fishers exact test, significant at p < 0.05. Definitions: D1Sa = approximal caries lesion in the outer half of the enamel; D1+2Sa = approximal enamel caries lesion on level 1 and approximal caries lesion more than halfway through the enamel but not passing the enamel-dentin junction; D1+2+3Sa = approximal enamel and dentin caries lesion on level 1+2 and approximal caries lesions extending into dentin; D1+2+3FSa = approximal enamel and dentin caries lesion on level 1+2+3 and approximal fillings.
Table 3 Caries prevalence at baseline and after two years, caries incidence and progression after 2 years (mean ± SD) Intervention group (n=237)
Control group (n=227)
Caries index
Baseline % (n)
2 years % (n)
Baseline % (n)
2 years % (n)
p-value*
D1+2Sa
0.88 (2.55)
1.26 (2.91)
0.74 (1.86)
1.58 (2.97)
0.07
D3Sa
0.03 (0.22)
0.08 (0.56)
0.03 (0.20)
0.07(0.27)
0.59
D3FSa
0.11 (0.44)
0.24 (0.82)
0.10 (0.38)
0.17 (0.56)
0.47
0.99 (2.15)
0.10
Incidence
0.66 (1.61)
*Mann-Whitney U-test and clustered permuted test, p < 0.05 significance level. Caries incidence = caries-free surfaces that develop into enamel lesions, dentin lesions or fillings in a period of two years.
caries and periodontal disease, fewer participants possessed such knowledge at baseline, although the majority knew the causes of gingival bleeding (questions 5–7). At the follow-up, a significantly larger number of individuals in the intervention group were able to correctly answer what caries means. In question 9, participants were asked to choose the best alternative for reducing the risk of caries; at baseline, more than half the participants in both groups chose the statement ‘eating sweets now and then’. After two years, the same proportion of participants, irrespective of group, knew that eating sweets ‘all at once’ may reduce the risk of tooth decay. Attitudes concerning tobacco use at baseline and after two years in the intervention and the control groups are presented in Table 4. The results generally showed a negative attitude towards the use of tobacco with the consequence that a majority of the participants were positively inclined towards all smoking bans (question 12). Half of the adolescents in both groups and after two years
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thought that they would not have tried smoking as adults (question 16, Table 4). Question 17 was directed only towards the intervention group and focused on having a dental hygienist working at school. About two-thirds of the participants felt that the dental hygienist contributed to better dental health among students; however, only 22% believed that dental hygienists would be able to help those who use tobacco to quit smoking. A majority responded that they themselves are responsible for their own oral health (Fig 2).
DISCUSSION The aim of this study was to evaluate the ability to influence adolescents’ caries incidence, knowledge and attitudes towards oral health and tobacco use through a school-based oral health intervention programme. Four schools with specific characteristics were selected and the schools were
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Table 4 Questions 10–14, distribution of answers about tobacco at baseline and after 2 years (in %) Intervention group Question
Baseline
2 year
10. Do you smoke? No No, but I’ve tried it No; I’ve quit Yes
N=242 82 14 2 2
N=241 75 18 4 3
11. Do you snuff? No No, but I’ve tried it No; I’ve quit Yes
N=242 90 9 0 1
N=242 85 12 0 3
12. I’m in favour of age limits for tobacco sale Yes Maybe No
N=242 87 9 4
N=229 87 9 4
13. It’s hard not use tobacco Yes Maybe No
N=240 66 19 15
N=229 65 20 15
14. There should be more education about tobacco in school Yes Maybe No
N=241 35 41 24
N=238 29 44 27
15. It should be forbidden to use tobacco in school Yes Maybe No
N=241 78 14 8
N=237 66 19 15
N=236 45
N=233 48
22 5 1 27
23 5 3 21
16. Mark the statements that match you As an adult I will not have tried smoking I will have tried smoking I smoke sometimes I smoke every day Don’t know
randomised into intervention and control groups since the randomisation of individuals was not possible for practical reasons. This may increase the risk of selection bias; if the participants had prior knowledge of the allocation, they might refuse to participate because of group pressure from their
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Control group OR
0.44
0.39
1.06
0.94
0.70
0.36
1.18
Baseline
2 year
N=226 83 13 1 3
N=228 77 14 2 7
N=228 92 7 0 1
N=227 89 7 0 4
N=226 91 6 3
N=227 85 8 7
N=222 73 14 13
N=228 70 17 13
N=225 30 45 25
N=227 25 48 27
N=225 84 13 3
N=225 77 14 9
N=214 46
N=221 55
21 3 1 29
22 6 4 13
OR
p-value
0.39
NS
0.50
NS
0.46
NS
0.79
NS
0.77
NS
0.48
NS
1.91
NS
classmates. Neither the schools nor the participants knew about the allocation in advance and none withdrew after the allocation had been made. The design might also increase the risk of influence from confounding factors. However, this risk was compensated by the choice of statistical method.
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Table 5 Questions 3–9, distribution of answers about oral health at baseline and after 2 years (%) Intervention group Question
Baseline
2 year
3. Are the teeth important? Yes, very important Rather important Not particularly important Not important at all
N=242 79 20 1 0
N=240 81 16 1 2
4. How often should you brush your teeth? Twice or more a day Once a day Once a week I don´t know
N=242 95 3 1 1
N=242 96 2 0 2
5. If the gums bleed, what’s wrong? Lack of sleep Eat too much candy Cavities Careless about toothbrushing Don’t know
N=242 0 1 3 79 17
N=229 0 3 4 86 7
6. What does caries mean? Bleeding gums Calculus Cavities Plaque Don’t know
N=241 2 12 21 47 18
N=238 1 11 38 40 10
7. What does periodontitis means? Tooth loss Gum inflammation Cavities Acid on teeth Don’t know
N=241 11 8 1 19 61
N=235 21 9 3 14 53
8. Why use toothpaste with fluoride? Tastes good Strengthens the teeth Makes foam Makes teeth whiter Don’t know
N=241 1 83 1 8 7
N=229 5 91 1 1 2
9. Which statement reduces the risk of getting cavities? Eating all the candy at once Eating every now and then Drink softdrinks between meals Don’t know
N=241 33 52 2 13
N=229 52 40 3 5
Control group OR
1.17
1.17
1.77
2.54
2.73
2.36
3.05
Baseline
2 year
N=229 80 19 2 0
N=229 74 22 3 1
N=229 97 3 0 1
N=228 91 7 1 1
N=229 1 4 4 70 21
N=228 2 2 3 80 13
N=229 1 13 21 48 17
N=227 2 11 18 52 17
N=228 10 11 1 10 68
N=228 11 12 2 16 59
N=229 2 84 1 8 5
N=227 5 81 2 8 4
N=228 34 58 0 8
N=223 48 43 4 5
OR
p-value
0.61
NS
0.24
0.02
2.30
NS
0.65
0.05
1.24
NS
0.75
NS
2.88
NS
The response options are dichotomised into ‘right’ and ‘wrong’ answers. The ‘right’ answer is indicated in bold. Other options are considered ‘wrong’.
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I appreciate education about oral health and tobacco I think it is good with a dental hygienist at school I belive that the dental hygienist improved adolescents’ oral health I am responsible for my own oral health I think the dental hygienist helps those who use tobacco to quit I believe it depends on the parents if you start to use tobacco
0
20
40 60 Percent
80
100
Fig 2 Distribution of answers, showing the participants’ opinion of the dental hygienist’s role at school.
Other factors that strengthened the quality of the method were the use of a control group and the fact that the examiner who read the bite-wings did not know to which group the participants belonged. The preventive programme in the present study included recurrent education about oral health and tobacco, fluoride varnish application every six month and other regularly performed preventive measures. The effects on caries activity were limited, although fewer individuals in the intervention group showed enamel caries after two years than in the control group. Regarding dentin caries, no significant differences were observed. Caries incidence was lower in the intervention group, although the difference was not statistically significant (p = 0.10) and the preventive fraction was 50%. Because the deviation in terms of DSa values was greater than calculated in the power assessment, a larger sample would have been needed to obtain significant differences. These findings are in line with previous studies by Moberg Sköld et al (2005) and two systematic reviews (Marinho et al, 2002; Petersson et al, 2004), which have shown a caries reduction of 30%–70% in fluoride varnish programmes. The effect on enamel but not on dentin caries corresponds well with previous observations reporting that enamel lesions accounted for more than 90% of caries reduction (Moberg Sköld et al, 2005). One explanation for the somewhat lower reduction in the present study might be that the intervention period was only 24 months compared with 36 months in the study by Moberg Sköld et al (2005). Another explanation could be that the caries prevalence in both groups was already low at
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baseline, which makes it difficult to achieve further improvements. In addition, caries today progresses relatively slowly, and therefore it is logical to expect that new caries lesions in the present study would be found in the outer half of the enamel. Even if the study period had been three years or more, it might not have shown a reduction in dentin caries. The fact that an effect on enamel caries was obtained strengthens the case for fluoride varnish as a useful preventive measure. However, other fluoride varnish programmes have reported no preventive effect in the permanent dentition of children aged 6–8 years who were followed up for up for two years after fluoride had been applied in the schools (Hardman et al, 2007, Milsom et al, 2011). Already at the study’s start, knowledge and attitudes in many areas were favourable among participants. Almost all participants stated that their teeth were important and significantly more adolescents in the intervention group knew that toothbrushing should be carried out twice a day. This is positive and in line with other studies carried out recently in Sweden (Hedman et al, 2006; Jensen et al, 2012). However, only a few participants could explain caries and periodontitis. After two years, significantly more individuals in the intervention group were able to answer the question ‘what does caries mean?’ correctly. In addition, almost twice as many in the intervention group (although not statistically significant due to small group size and low spread) knew what periodontitis meant. Adolescents in the intervention group also had better knowledge about the recommended toothbrushing frequency and the effects of fluoridated toothpaste. In fact, the participants in the intervention group consistently displayed more knowledge about oral health than did the participants in the control group. Knowledge about caries related to dietary habits was limited before the study started, but improved in both groups during the study period. One explanation for the improvement among participants might be that improved knowledge is attributable to the fact that the children simply grew older, as described in other studies (Hedman et al, 2006, Tolvanen et al, 2009). Concerning attitudes toward tobacco, no differences between the groups could be seen after two years. Approximately half of the participants in both groups did not see themselves as future smokers/ snuffers, a observation also reported in other studies (Nilsson et al, 2006; Hedman et al, 2010). Caries is unevenly distributed in the Swedish population. Two different strategies to prevent car-
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ies may be used, population-based and individualbased. High-risk individuals are, however, difficult to identify and reach using a preventive message; it is also difficult to obtain compliance (Hausen, 2004). In addition, since very few individuals in Sweden suffer from severe caries problems, the greatest number of carious lesions will be found among the population with low and medium risk (Rose, 2001; Marthaler, 2004). School-based oral health programmes address all adolescents and adolescents at the highest risk of oral diseases tend to benefit the most from preventive measures. A relationship between knowledge, attitudes and behaviour among schoolchildren has been described, but it has also been shown that children are ready to assimilate new knowledge and attitudes and change their behaviour during different periods in life. Thus, it is important that the promotion be prolonged and not just implemented as a time-limited campaign (Tolvanen et al, 2010). Other advantages of an oral health intervention programme in school, as in the present study, are that the implementation of dental care is more efficient from the perspectives of the adolescents and dental personnel alike. Adolescents save time by eliminating trips to the dental clinic and those with the highest risk have a greater number of preventive measures performed. Schools may provide arenas for oral health care and services (WHO, 2003) and can be useful sources for improving oral health among adolescents in a population. Schools also have a responsibility for child and adolescent health (Tones and Tilford, 2001). Health intervention programmes in schools should include components directed towards both the individual and the school environment (Sellström and Bremberg, 2006). When the individual meets the dental hygienist at school instead of the clinic, it is easier to leave the role of the patient to focus on factors of daily living habits and health promotion. Health promotion should include cooperation and a common understanding of health messages among health workers, educators and students. Therefore, the dental hygienist who is trained to support people on health issues may serve as a ‘bridge’ between different school groups to motivate those who want to promote adolescent health.
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CONCLUSION In conclusion, the two-year school-based oral health programme influenced the prevalence of enamel caries and showed some positive changes in knowledge about oral health among the adolescents. In addition, the adolescents themselves described the programme as positive and reported that the presence of a dental hygienist in school would improve their oral health.
ACKNOWLEDGEMENTS We thank the dental hygienists Marie Lindén and Carina Landh for their skillful implementation of the oral health programme, and the dentist Ulla Thörnblom for evaluating the radiographs. We also thank Lisa Wernroth at Uppsala Clinic Research (UCR) for her statistical analysis. Finally, the authors would like to thank Uppsala County and Public Dental Health for financial support.
REFERENCES 1. Bagramian RA, Garcia-Godoy F, Volpe AR. The global increase in dental caries. A pending public health crisis. Am J Dent 2009;22:3–8. 2. Batchelor P, Sheiham A.The limitations of a ‘high-risk’ approach for the prevention of dental caries. Community Dent Oral Epidemiol 2002;30:302–312. 3. Byrappagari D, Mascarenhas AK, Chaffin JG. Association of caries and tobacco risk with Dental Fitness Classification. Mil Med 2006;171:415–419. 4. Cohen J. A coefficient of agreement for nominal scales. Educ Psychol Measurement 1960;20:37–46. 5. Costacurta M, Di Renzo L, Bianchi A, Fabiocchi F, De Lorenzo A, Docimo R. Obesity and dental caries in paediatric patients. A cross-sectional study. Eur J Paediatr Dent 2011;12:112–116. 6. Fejerskov O. Changing paradigms in concepts on dental caries: consequences for oral health care. Caries Res 2004;38:182–191. 7. Flay BR. School-based smoking prevention programs with the promise of long-term effects. Tob Induc Dis 2009;5:6. 8. Galanti MR, Rosendahl I, Post A; Gilljam H. Early gender differences in adolescent tobacco use–-the experience of a Swedish cohort. Scand J Public Health 2001;29:314–317. 9. Gröndahl HG, Hollender L, Malmcrona E, Sundquist B. Dental caries and restorations in teenagers. I. Index and score system for radiographic studies of proximal surfaces. Swed Dent J 1977;1:45–50. 10. Hardman MC, Davies GM, Duxbury JT, Davies RM. A cluster randomised controlled trial to evaluate the effectiveness of fluoride varnish as a public health measure to reduce caries in children. Caries Res 2007;41:371–376. 11. Hausen H. How to improve the effectiveness of cariespreventive programs based on fluoride. Caries Res 2004;38:263–267.
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Hedman et al 12. Hausen H, Karkkainen S, Seppä L. Application of the highrisk strategy to control dental caries. Community Dent Oral Epidemiol 2000;28:26–34. 13. Hedman E, Riis U, Gabre P. The impact of behavioural interventions on young people’s attitudes toward tobacco use. Oral Health Prev Dent 2010;8:23–32. 14. Hedman E, Ringberg C, Gabre P. Knowledge of and attitude to oral health and oral diseases among young adolescents in Sweden. Swed Dent J 2006;30:147–154. 15. Hu FB, Goldberg J, Hedeker D, Flay BR, Pentz MA. Comparison of population-averaged and subject-specific approaches for analyzing repeated binary outcomes. Am J Epidemiol 1998;147:694–703. 16. Jensen O, Gabre P, Sköld UM, Birkhed D. Is the use of fluoride toothpaste optimal? Knowledge, attitudes and behaviour concerning fluoride toothpaste and toothbrushing in different age groups in Sweden. Community Dent Oral Epidemiol 2012;40:175–184. 17. Kay E, Locker D. A systematic review of the effectiveness of health promotion aimed at improving oral health. Community Dent Health 1998;15:132–144. 18. Kelder SH, Perry CL, Klepp KI, Lytle LL. Longitudinal tracking of adolescent smoking, physical activity, and food choice behaviors. Am J Public Health 1994;84:1121–1126. 19. Kuusela S, Honkala E, Rimpela A, Karvonen S, Rimpela M. Trends in toothbrushing frequency among Finnish adolescents between 1977 and 1995. Community Dent Health 1997;14:84–88. 20. Marinho VC, Higgins JP, Logan S, Sheiham A. Fluoride varnishes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev 2002;CD002279. 21. Marinho VC, Higgins JP, Logan S, Sheiham A. Fluoride mouthrinses for preventing dental caries in children and adolescents. Cochrane Database Syst Rev 2003a; CD002284. 22. Marinho VC, Higgins JP, Sheiham A, Logan S. Fluoride toothpastes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev 2003b; CD002278. 23. Marthaler TM. Changes in dental caries 1953–2003. Caries Res 2004;38:173–181. 24. Milsom KM, Blinkhorn AS, Walsh T, Worthington HV, Kearney-Mitchell P, Whitehead H, Tickle M. A cluster-randomized controlled trial: fluoride varnish in school children. J Dent Res 2011;90:1306–1311. 25. Moberg Sköld U, Petersson LG, Lith A, Birkhed D. Effect of school-based fluoride varnish programmes on approximal caries in adolescents from different caries risk areas. Caries Res 2005;39:273–279. 26. Nilsson M, Stenlund H, Bergström E, Weinehall L, Janlert U. It takes two: reducing adolescent smoking uptake through sustainable adolescent-adult partnership. J Adolesc Health 2006;39:880–886.
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27. O’Dea JA, Abraham S. Improving the body image, eating attitudes, and behaviors of young male and female adolescents: a new educational approach that focuses on self-esteem. Int J Eat Disord 2000;28:43–57. 28. Papapanou PN. Epidemiology of periodontal diseases: an update. J Int Acad Periodontol 1999;1:110–116. 29. Petersen PE. World Health Organization global policy for improvement of oral health – World Health Assembly 2007. Int Dent J 2008;58:115–121. 30. Petersson LG, Twetman S, Dahlgren H, Norlund A, Holm AK, Nordenram G, Lagerlöf F, Söder B, Källestål C, Mejare I, Axelsson S, Lingström P. Professional fluoride varnish treatment for caries control: a systematic review of clinical trials. Acta Odontol Scand 2004;62:170–176. 31. Roosaar A, Yin L, Johansson AL, Sandborgh-Englund G, Nyren O, Axell, T. A long-term follow-up study on the natural course of oral leukoplakia in a Swedish populationbased sample. J Oral Pathol Med 2007;36:78–82. 32. Rose G. Sick individuals and sick populations 1985. Bull World Health Organ 2001;79:990–996. 33. Sellström E, Bremberg S. Is there a “school effect” on pupil outcomes? A review of multilevel studies. J Epidemiol Community Health 2006;60:149–255. 34. Skeie MS, Espelid I, Skaare AB, Gimmestad A. Caries patterns in an urban preschool population in Norway. Eur J Paediatr Dent 2005;6:16–22. 35. St Leger L. Schools, health literacy and public health: possibilities and challenges. Health Promot Int 2001;16:197– 205. 36. Stedman MR, Gagnon DR, Lew RA, Solomon DH, Losina E, Alan Brookhart M. A SAS macro for a clustered permutation test. Comput Methods Programs Biomed 2009;95:89–94. 37. Tolvanen M, Lahti S, Poutanen R, Seppä L, Hausen H. Children’s oral health-related behaviors: individual stability and stage transitions. Community Dent Oral Epidemiol 2010;38:445–452. 38. Tolvanen M, Lahti S, Poutanen R, Seppä L, Pohjola V, Hausen H. Changes in children’s oral health-related behavior, knowledge and attitudes during a 3.4-yr randomized clinical trial and oral health-promotion program. Eur J Oral Sci 2009;117:390–397. 39. Tones K, Tilford S. Health promotion: effectiveness, efficiency and equity. Cheltenham: Nelson Thornes Ltd, 2001. 40. Turner L, Mermelstein R, Flay B. Individual and contextual influences on adolescent smoking. Ann N Y Acad Sci 2004;1021:175–197. 41. WHO. The World Oral Health Report, shaping the future. Geneva, 2003.
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Dental Hygienists Working in Schools – A Two-year Oral Health Intervention Programme in Swedish Secondary Schools Eva Hedmana/Pia Gabreb/Dowen Birkhedc Purpose: To investigate the possibility of influencing adolescents’ caries incidence, knowledge and attitudes to oral health and tobacco through a school-based oral health intervention programme. Materials and Methods: Four schools in a county in Sweden were randomised to one intervention and one control group. At the intervention schools, two dental hygienists worked 4 h every week for two years. Health education and preventive measures, such as fluoride varnish treatments every 6 months, were performed. The control group had no intervention. The study included a total of 534 participants aged 12–16 years. Outcome variables of the study were 1) caries incidence assessed on bite-wing radiographs and 2) knowledge and attitudes measured through questionnaires. Results: The intervention programme impacted on the incidence of enamel caries, while no effect on dentin caries could be seen. Data from the questionnaires showed that the adolescents considered their teeth as important. Adolescents in the intervention group had better knowledge about oral health and oral hygiene compared to the control group after the two years, but no impact on attitudes toward tobacco could be seen. A majority of the adolescents were positive to the education about oral health and tobacco and they believed that the dental hygienists would help them improve their oral health. Conclusions: Although the effects of the intervention as regards to caries incidence, knowledge and attitudes were limited, the presence of dental hygienists in school was appreciated by the adolescents and seemed to increase their interest in their oral health. Key words: adolescents, caries, fluoride varnish, oral health, prevention Oral Health Prev Dent 2015;13:177-188 doi: 10.3290/j.ohpd.a32132
D
ental caries has decreased considerably among children and adolescents over the last four decades in industrialised countries, mainly due to the widespread use of fluoride toothpaste (Marinho et al, 2003b). However, threats to oral health have a
Dental Hygienist, Department of Preventive Dentisty, Public Dental Health, Uppsala County Council, Uppsala, Sweden; Department of Cariology, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Sweden.
b
Dentist, Department of Preventive Dentisty, Public Dental Health, Uppsala County Council, Uppsala, Sweden; Department of Cariology, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Sweden.
c
Professor, Department of Cariology, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Sweden.
Correspondence: Eva Hedman, Department of Preventive Dentisty, Public Dental Health, Ulleråkersvägen 21, SE- 750 17 Uppsala, Sweden. Tel: +46-18-611-6439, Fax: +46-18-611-6120. Email: [email protected]
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Submitted for publication: 06.11.12; accepted for publication: 14.05.13
been increasing during the same period because of change of life-style factors. The risk factors for oral disease are often the same as those implicated in major general diseases (Petersen, 2008). Thus, a large and frequent sugar intake can cause not only caries, but also overweight and diabetes (Costacurta et al, 2011). Tobacco use is also associated with an increased risk of oral diseases, such as periodontal diseases and mucosal lesions (Papapanou, 1999; Byrappagari et al, 2006; Roosaar et al, 2007). Many young people start using tobacco during adolescence and almost all debuts occur between the ages of 11 and 16 (Galanti et al, 2001; Turner et al, 2004). Adolescence is an important time of life for health promotion and it is known that toothbrushing, smoking, physical activity and dietary habits are established during this period (Kelder et al,
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Four elementary schools, 556 adolescents total
534 adolescents agreed to participate
Did not complete four fluoride varnish treatments: N= 10*
No X-rays at baseline and/or after two years: N=33*
Did not answer the questionaire at baseline and/or after two years: N=29*
Two intervention schools, N=270 Proportion of girls: 45% Proportion of adolescents with immigrant background: 9%
Two control schools, N=264 Proportion of girls: 49% Proportion of adolescents with immigrant background: 7%
- Clinical examination including bite-wing radiographs - Caries risk assessment - Preventive measures according to individual indications
- Clinical examination including bite-wing radiographs - Caries risk assessment - Preventive measures according to individual indications
Questionnaire
Questionnaire
School-based oral health intervention (Table 1)
Two years after baseline examination: Clinical examination including bitewing radiographs
Two years after baseline examination: Clinical examination including bitewing radiographs
No X-rays at baseline and/or after two years: N=37*
Did not answer the questionaire at baseline and/or after two years: N=35*
Questionnaire
Questionnaire
Completed all parts: N=212 According to intention to treat:** N=237 included in caries analysis N=242 included in questionnaire analysis
Completed all parts: N=208 According to intention to treat:** N=227 included in caries analysis N=229 included in questionnaire analysis
*The same individual can appear in more than one drop-out box
**All adolescents who had agreed to participate in the study from the beginning were included in the final analysis.
Fig 1 Flow chart of the study.
1994, Kuusela et al, 1997). Adolescents spend thousands of hours in the school environment, which makes the school a natural arena for health promotion. Studies on oral health promotion programmes at school have shown varying results and it is unclear which type of intervention is the most effective (Kay and Locker, 1998; St Leger, 2001). Systematic reviews stress the use of fluoride and its caries-reducing effects (Marinho et al, 2003a; Marinho et al, 2003b). Despite improved dental health in Sweden, caries is still a problem in many children, in which not using fluoride toothpaste properly, bad oral hygiene and dietary habits play a key role (Fejerskov, 2004). Caries is also related to socioeconomic conditions, such as the educational level of the parents and
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immigrant backgrounds (Skeie et al, 2005). A large proportion of children in Sweden have had some dental caries by the time they are 12–16 years old, especially when approximal enamel caries also is included. Around 10%–15% of children and adolescents have serious problems with caries, a proportion that has remained unchanged over a long period (Bagramian et al, 2009). During the 1980s, when only a small proportion of the children and adolescents were suffering from poor dental health, many Swedish counties changed from a population-oriented approach to an individual high-risk strategy. Such a high-risk strategy involves the identification of individuals at risk for caries, who are then offered individually designed preventive measures (Hausen et al, 2000).
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Table 1 Components of the school-based oral health intervention Intervention components
Description
Parent meetings
At the start of the study in grades 6–9
Population Education about oral health
All participants were offered lessons once each semester for 2 years. Content: toothbrushing with fluoride toothpaste twice per day, the impact of daily habits on oral health, avoiding sugar-containing food and drink, risks of tobacco use Method: student-centered learning, values clarification Aids: books, films, photos, exhibition about sugar in food, tobacco props that shows health risks and financial disadvantages
Fluoride varnish treatments
Every 6 months in grades 6–9
Spontaneous visits
Participants in grades 6–9 were able to attend the school dental clinic on their own initiative
High risk Screening and prophylaxis
Participants at high risk of dental diseases were offered preventive measures and health dialogues at the school clinic
The effectiveness of this high-risk strategy has been questioned since many children with low and moderate risk were also developing new caries (Batchelor and Sheiham, 2002). The most effective way to reduce caries may therefore be to focus on population-based interventions. Programmes carried out in school include all children in a natural way. Moreover, young people with the highest risk for caries have the most to gain from this strategy (Moberg Sköld et al, 2005). The aim of the present investigation was therefore to study the possibility of influencing adolescents’ caries incidence, knowledge and attitudes toward oral health and tobacco use through a school-based oral health intervention programme, carried out by two trained dental hygienists who regularly visited the schools.
MATERIALS AND METHODS Study design An oral health intervention programme was conducted in the county of Uppsala, Sweden. Two intervention and two control schools were included in a longitudinal experimental study (Fig 1). The programme was introduced in August 2009 in grades 6, 7 and 8 of four secondary schools, when the students were 13, 14 and 15 years old, respectively. It ran for 2 years until the students finished grades 7, 8 and 9 (in June 2011). Two dental hygienists, one for each intervention school, imple-
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mented the programme; they were in school 4 hours per week during the semesters. The hygienists worked on oral health education and preventive measures (Table 1) and had been trained to perform education and preventive measures in similar ways in both schools. The effect of the intervention programme was evaluated and caries incidence, knowledge and attitudes to oral health and tobacco use were measured in the study in terms of study outcomes. During the study and at the end of each semester, the methods and contents of the intervention were discussed in meetings with the dental hygienists and one of the authors (EH). No interventions were carried out in the control group, but the effects of caries incidence, knowledge and attitudes were measured in the same way as in the intervention group (Fig 1). The study was approved by the Ethics Committee, Faculty of Medicine, Uppsala University, Sweden. Informed consent was obtained from all participants and their parents/guardians before the study started.
Subjects For practical reasons, the participants could not be randomly selected into test and control groups. Instead, four schools were chosen based on specific inclusion criteria (see below). After the schools had been selected, it was decided by drawing lots which should be the intervention schools and which
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should be control schools. Inclusion criteria were: 1) the school should have a student population of at least 100 students, 2) grades 6–8 should be represented, 3) the school should not be situated in an area with low caries risk and 4) the school must be able to offer a special room for the dental hygienist during a 2-year period. The study design is shown in Fig 1. In accordance with the principles of intention-totreat, all adolescents who had agreed to participate in the study from the beginning were included in the final analysis, assuming that radiographs or questionnaires from baseline and after two years were available (Fig 1). The project was introduced to adolescents, parents and school staff through a letter and meetings in school before the study began.
Education about oral health and tobacco The programme consisted of recurrent education about oral health and tobacco once each semester over a two-year period. The education took place in conjunction with ordinary lessons in Biology and Chemistry, during which the dental hygienist cooperated with the ordinary school teachers. The hygienists were trained in working with an approach called ‘Values Clarification’, a methodology based on educational theories of cooperative, interactive and student-centred learning (O’Dea and Abraham, 2000). The aim was to influence people in groups, their attitudes and behaviour in matters of lifestyle. It was important not to pre-arrange the teaching in detail as the lesson aimed to stimulate communication among the adolescents, dental hygienist and school staff. The focus was on problems that the adolescents themselves had defined as important and on generating an interest in health-promoting behaviours (Flay, 2009; Hedman et al, 2010). The contents of the educational programme and methods and aids used are described in Table 1. The dental hygienist, school teachers and adolescents discussed issues involving oral health, including dietary habits, oral hygiene and tobacco use. Special attention was devoted to the negative oral health consequences of frequent consumption of sugar-containing products and snacks, the importance of toothbrushing twice a day with fluoride toothpaste and the harmful effects of smoking and snuffing tobacco.
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Open clinic in school The dental hygienist had an open clinic for 4 hours each week at school, during which screenings, fluoride varnish treatments and other preventive measures were carried out regularly. Fluoride treatment: All students were offered fluoride varnish treatment every six months. The adolescents arrived at the school clinic in groups of two to three students. If necessary, the teeth were cleaned with a toothbrush and dental floss. Cotton rolls were placed in the vestibulum of the upper and lower jaws and the varnish (Duraphat 22.6 mg F/ml, Colgate; Piscataway, NJ, USA) was applied thinly with a small cotton stick (Quick-Stick, Dentsolv; Saltsjöbo, Sweden). All approximal surfaces, from the distal surface of the canines and to the mesial surfaces of the second molars, were treated. The adolescents were asked not to eat for a few hours and abstain from cleaning their teeth until the following day.
Preventive measures Adolescents in the intervention schools who were identified as at risk of caries were offered individualised preventive measures at the school clinic. They had been identified as high-risk patients by a dentist or dental hygienist at the regular check-up at the public dental clinic. Based on the patient’s individual history, where social, medical and oral conditions were considered, the adolescents were given dietary advice, oral hygiene instructions and fluoride treatments (varnish, rinsing solution, toothpaste) at school. Through dialogue, the hygienist tried to motivate the adolescents to improve their oral health behaviour. Adolescents who did not choose to receive supplemental preventive measures at school were offered the same treatment at the dental clinic. In the control schools, all adolescents who were identified as at risk of caries received the same preventive care at the dental clinic. On their own initiative, the adolescents and school staff could visit the dental hygienist for advice and help; oral-care products (toothbrushes and toothpaste) were for sale at a low cost. She also supported school staff, for instance, by advising which products should be sold in the school cafeteria and participating in various health activities at the school and at parent meetings.
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Caries registration During a clinical examination by the adolescent’s usual dentist or dental hygienist at the public dental clinic, two or four bite-wing radiographs were taken before the study started and were then repeated approximately two years later. All radiographs were assessed using a high resolution LCD screen (Olorin VistaLine VC 1900, Olorin; Kungsbacka, Sweden) and were analysed blindly as described by Gröndahl et al (1977) by one and the same dentist. Before the study began, the dentist’s assessments of radiographs were calibrated with those of another dentist with great experience in caries research (author P.G.). A protocol was designed and data concerning caries risk, date of last previous clinical examination and bite-wing radiographs were collected from the records. The caries status of the approximal surfaces in permanent teeth was registered and, in addition, it was noted if any tooth surface was missing or if caries registration was not possible due to poor quality of the films. All approximal surfaces of permanent premolars and molars were scored as follows (modified from Moberg Sköld et al, 2005): 0 = caries free, 1 = caries lesion in the outer half of the enamel; 2 = caries lesion more than halfway through the enamel without passing the enameldentin junction, 3 = caries lesion extending into dentin, 4 = filled surfaces, 5 = surfaces impossible to score and 6 = teeth not yet erupted. If a tooth surface wase initally caries-free and later developed an enamel or dentin lesion or filling, this was defined as ‘caries incidence’ (0–1–4). All surfaces with caries at baseline and where the caries lesion had a higher value after two years were noted as ‘caries progression’. Preventive fraction (PF), the proportion of lesions that may be prevented, was calculated and expressed as a percentage of the difference of mean caries incidence between control and intervention groups. The dentist responsible for scoring the study results did not know if the patient belonged to the intervention or control group.
Questionnaire Information about adolescents’ knowledge of and attitudes toward oral health and tobacco use was collected through questionnaires at both the start and the end of the study at the intervention and control schools. At the start of the study, it con-
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sisted of 16 structured questions with fixed answers, referred to oral health, dietary habits and tobacco use and was partly based on a questionnaire used in a previous study (Hedman et al, 2006). The questionnaire used in the intervention schools at the end of the study consisted of the same 16 questions, in addition to one question about the intervention programme. The response options were dichotomised into ‘right’ and ‘wrong’ answers.
Statistical analyses A power calculation was made to determine the number of participants in the study. Power was calculated for two variables: 1) expected caries development and 2) expected difference in attitude to oral health and tobacco use, based on the results of studies by Moberg Sköld et al (2005) and Hedman et al (2006). A sample size of 180 in each group was calculated to have 80% power to detect a mean difference of 0.15 in DSa (number of approximal tooth surfaces with dentin lesions). Taking into account that a nonparametric test should be performed, approximately 200 school children in each group were needed. All data were single key entered into a PheedIt database. A logical check of all data was performed with an error rate of 0.02%. Analysis was based on all adolescents included in the study at baseline according to the intention-totreat principles, which means that all the randomised adolescents’ data were used for analysis regardless of whether or not they participated in all interventions. Two hypotheses were tested in the study: 1) no association exists between intervention and caries and 2) no association exists between intervention and knowledge of/attitude toward oral health and tobacco. Dichotomised caries incidence and progression at the end of the study and dichotomised knowledge/attitude at the end of the study were the response variables. The results were expressed as odds ratios (OR) and corresponding 95% confidence intervals (CI) with the associated p-value. The interaction between time and group was tested by using ‘discordant pairs’ for the control and treatment groups in a single table as well as by performing Fisher’s exact test (Hu et al, 1998) and applying a clustered permutation test with 1000 permutations (Stedman et al, 2009). If the outcome of interest is attitude concerning tobacco use, the ‘discordant pairs’ are the children that changed
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attitude concerning tobacco use during the study, i.e. a different outcome at follow-up compared to baseline. In order to evaluate differences in caries incidence and progression between the two groups, the number of surfaces with an incidence and/or caries progression was calculated for each participant. The Mann-Whitney U-test was calculated and a clustered permutation test carried out. Intra-examiner reliability was analysed with Cohen’s kappa coefficient. All statistical analyses were performed with two-sided tests at the 0.05 level of significance.
RESULTS Drop-outs and intra-examiner reliability In total, 556 adolescents from the four schools were invited and 534 agreed to participate in the study. The distribution of individuals between the intervention and control groups was even and no differences between sex or country of birth were observed (Fig 1). Of those 270 subjects at the intervention schools who agreed to participate, 10 did not complete all parts of the intervention. In the caries analysis, 237 and 227 adolescents in the intervention and control groups, respectively, were included. The corresponding number in the analysis of questionnaires was 242 and 229 subjects, respectively (Fig 1). The reasons for not taking part in all parts of the intervention, not having available radiographs or having answered the questionnaire twice were that the adolescents were seeing a private dentist, had moved from the area or refused to participate. The proportions of drop-outs were equal in both groups. The percentage of tooth surfaces for which the quality of the radiographs was inadequate for caries assessment or the tooth had not yet erupted at baseline was 12% in the intervention group and 13% in the control group. After two years, the intervention group exhibited 14% surfaces that did not allow caries assessment and the corresponding figure for the control group was 11%. The intra-examiner reliability was measured by allowing the investigator to repeat the examination of the bite-wing radiographs for 50 participants selected on a random basis. Kappa values for intra-observer agreement for both enamel and manifest caries were 0.87 (Cohen, 1960).
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Caries At baseline, 74% of the participants in the intervention group and 72% in the control group were caries free, defined as no approximal enamel or dentin carious lesions on levels 1+2+3 nor approximal fillings (D1+2+3FSa = 0); approximately 24% in both groups had approximal enamel caries on level 1 and approximal enamel carious lesions more than halfway through the enamel but not passing the enamel-dentin junction (D1+2Sa ≥1). After two years, the number of caries-free individuals had decreased by 5% in the intervention group and by 9% in the control group (Table 2). The prevalence of enamel caries level 1 increased less in the intervention group than in the control group. After two years, the number of individuals who had enamel caries level 1 (D1Sa) had increased by 2% among the individuals in the intervention group as compared with 12% in the control group (p < 0.01, Table 2). Caries prevalence, incidence and progression at baseline and after two years are illustrated in Table 3. There were no differences in caries prevalence when the study began. After two years, the caries incidence was lower, although not statistically significant for the adolescents in the intervention group (p = 0.10). The preventive fraction (PF), measured by incidence of approximal caries as the threshold, was 50% for the intervention group as compared with that of the control group.
Knowledge and attitudes At baseline, the intervention and control groups showed similar distributions with regard to sex, country of birth and tobacco use. A total of 8% of the participants had immigrant backgrounds and the use of tobacco was generally low in the entire population studied (Fig 1, Table 4). Attitudes and knowledge in most areas were favourable both at baseline and at the end of two years (Table 5). The majority of the participants in both groups and on both occasions reported that their teeth were ‘very important’ or ‘rather important’ (question 3). Significantly more adolescents in the intervention group stated that toothbrushing should be carried out twice a day (question 4). There were also more adolescents in the intervention group, although this was not significant (p = 0.067), who knew the positive effects of using fluoridated toothpaste (question 8). Concerning
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Table 2 Proportions and numbers of individuals with approximal caries lesions and fillings in intervention and control groups at baseline and after 2 years Intervention group (n=237)
Control group (n=227)
Baseline % (n)
2 years % (n)
OR (CI)
Baseline % (n)
2 years % (n)
OR (CI)
p-value*
D1Sa ≥ 1
23.2 (55)
24.9 (59)
1.2 (0.7-2.2)
20.7 (47)
33.0 (75)
5.0 (2.2-11)
0.002
D1+2Sa ≥ 1
24.5 (58)
27.8 (66)
1.5 (0.8-2.8)
24.2 (55)
34.4 (78)
3.9 (1.9-9.8)
0.07
D1+2+3Sa ≥ 1
24.9 (59)
28.3 (68)
1.5 (0.8-2.9)
25.1 (57)
34.8 (79)
3.4 (1.6-7.0)
0.09
D1+2+3FSa ≥ 1
26.2 (62)
31.6 (75)
2.0 (1.0-4.1)
27.8 (63)
36.6 (83)
3.5 (1.5-7.4)
0.28
Caries index
*Fishers exact test, significant at p < 0.05. Definitions: D1Sa = approximal caries lesion in the outer half of the enamel; D1+2Sa = approximal enamel caries lesion on level 1 and approximal caries lesion more than halfway through the enamel but not passing the enamel-dentin junction; D1+2+3Sa = approximal enamel and dentin caries lesion on level 1+2 and approximal caries lesions extending into dentin; D1+2+3FSa = approximal enamel and dentin caries lesion on level 1+2+3 and approximal fillings.
Table 3 Caries prevalence at baseline and after two years, caries incidence and progression after 2 years (mean ± SD) Intervention group (n=237)
Control group (n=227)
Caries index
Baseline % (n)
2 years % (n)
Baseline % (n)
2 years % (n)
p-value*
D1+2Sa
0.88 (2.55)
1.26 (2.91)
0.74 (1.86)
1.58 (2.97)
0.07
D3Sa
0.03 (0.22)
0.08 (0.56)
0.03 (0.20)
0.07(0.27)
0.59
D3FSa
0.11 (0.44)
0.24 (0.82)
0.10 (0.38)
0.17 (0.56)
0.47
0.99 (2.15)
0.10
Incidence
0.66 (1.61)
*Mann-Whitney U-test and clustered permuted test, p < 0.05 significance level. Caries incidence = caries-free surfaces that develop into enamel lesions, dentin lesions or fillings in a period of two years.
caries and periodontal disease, fewer participants possessed such knowledge at baseline, although the majority knew the causes of gingival bleeding (questions 5–7). At the follow-up, a significantly larger number of individuals in the intervention group were able to correctly answer what caries means. In question 9, participants were asked to choose the best alternative for reducing the risk of caries; at baseline, more than half the participants in both groups chose the statement ‘eating sweets now and then’. After two years, the same proportion of participants, irrespective of group, knew that eating sweets ‘all at once’ may reduce the risk of tooth decay. Attitudes concerning tobacco use at baseline and after two years in the intervention and the control groups are presented in Table 4. The results generally showed a negative attitude towards the use of tobacco with the consequence that a majority of the participants were positively inclined towards all smoking bans (question 12). Half of the adolescents in both groups and after two years
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thought that they would not have tried smoking as adults (question 16, Table 4). Question 17 was directed only towards the intervention group and focused on having a dental hygienist working at school. About two-thirds of the participants felt that the dental hygienist contributed to better dental health among students; however, only 22% believed that dental hygienists would be able to help those who use tobacco to quit smoking. A majority responded that they themselves are responsible for their own oral health (Fig 2).
DISCUSSION The aim of this study was to evaluate the ability to influence adolescents’ caries incidence, knowledge and attitudes towards oral health and tobacco use through a school-based oral health intervention programme. Four schools with specific characteristics were selected and the schools were
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Table 4 Questions 10–14, distribution of answers about tobacco at baseline and after 2 years (in %) Intervention group Question
Baseline
2 year
10. Do you smoke? No No, but I’ve tried it No; I’ve quit Yes
N=242 82 14 2 2
N=241 75 18 4 3
11. Do you snuff? No No, but I’ve tried it No; I’ve quit Yes
N=242 90 9 0 1
N=242 85 12 0 3
12. I’m in favour of age limits for tobacco sale Yes Maybe No
N=242 87 9 4
N=229 87 9 4
13. It’s hard not use tobacco Yes Maybe No
N=240 66 19 15
N=229 65 20 15
14. There should be more education about tobacco in school Yes Maybe No
N=241 35 41 24
N=238 29 44 27
15. It should be forbidden to use tobacco in school Yes Maybe No
N=241 78 14 8
N=237 66 19 15
N=236 45
N=233 48
22 5 1 27
23 5 3 21
16. Mark the statements that match you As an adult I will not have tried smoking I will have tried smoking I smoke sometimes I smoke every day Don’t know
randomised into intervention and control groups since the randomisation of individuals was not possible for practical reasons. This may increase the risk of selection bias; if the participants had prior knowledge of the allocation, they might refuse to participate because of group pressure from their
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Control group OR
0.44
0.39
1.06
0.94
0.70
0.36
1.18
Baseline
2 year
N=226 83 13 1 3
N=228 77 14 2 7
N=228 92 7 0 1
N=227 89 7 0 4
N=226 91 6 3
N=227 85 8 7
N=222 73 14 13
N=228 70 17 13
N=225 30 45 25
N=227 25 48 27
N=225 84 13 3
N=225 77 14 9
N=214 46
N=221 55
21 3 1 29
22 6 4 13
OR
p-value
0.39
NS
0.50
NS
0.46
NS
0.79
NS
0.77
NS
0.48
NS
1.91
NS
classmates. Neither the schools nor the participants knew about the allocation in advance and none withdrew after the allocation had been made. The design might also increase the risk of influence from confounding factors. However, this risk was compensated by the choice of statistical method.
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Table 5 Questions 3–9, distribution of answers about oral health at baseline and after 2 years (%) Intervention group Question
Baseline
2 year
3. Are the teeth important? Yes, very important Rather important Not particularly important Not important at all
N=242 79 20 1 0
N=240 81 16 1 2
4. How often should you brush your teeth? Twice or more a day Once a day Once a week I don´t know
N=242 95 3 1 1
N=242 96 2 0 2
5. If the gums bleed, what’s wrong? Lack of sleep Eat too much candy Cavities Careless about toothbrushing Don’t know
N=242 0 1 3 79 17
N=229 0 3 4 86 7
6. What does caries mean? Bleeding gums Calculus Cavities Plaque Don’t know
N=241 2 12 21 47 18
N=238 1 11 38 40 10
7. What does periodontitis means? Tooth loss Gum inflammation Cavities Acid on teeth Don’t know
N=241 11 8 1 19 61
N=235 21 9 3 14 53
8. Why use toothpaste with fluoride? Tastes good Strengthens the teeth Makes foam Makes teeth whiter Don’t know
N=241 1 83 1 8 7
N=229 5 91 1 1 2
9. Which statement reduces the risk of getting cavities? Eating all the candy at once Eating every now and then Drink softdrinks between meals Don’t know
N=241 33 52 2 13
N=229 52 40 3 5
Control group OR
1.17
1.17
1.77
2.54
2.73
2.36
3.05
Baseline
2 year
N=229 80 19 2 0
N=229 74 22 3 1
N=229 97 3 0 1
N=228 91 7 1 1
N=229 1 4 4 70 21
N=228 2 2 3 80 13
N=229 1 13 21 48 17
N=227 2 11 18 52 17
N=228 10 11 1 10 68
N=228 11 12 2 16 59
N=229 2 84 1 8 5
N=227 5 81 2 8 4
N=228 34 58 0 8
N=223 48 43 4 5
OR
p-value
0.61
NS
0.24
0.02
2.30
NS
0.65
0.05
1.24
NS
0.75
NS
2.88
NS
The response options are dichotomised into ‘right’ and ‘wrong’ answers. The ‘right’ answer is indicated in bold. Other options are considered ‘wrong’.
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I appreciate education about oral health and tobacco I think it is good with a dental hygienist at school I belive that the dental hygienist improved adolescents’ oral health I am responsible for my own oral health I think the dental hygienist helps those who use tobacco to quit I believe it depends on the parents if you start to use tobacco
0
20
40 60 Percent
80
100
Fig 2 Distribution of answers, showing the participants’ opinion of the dental hygienist’s role at school.
Other factors that strengthened the quality of the method were the use of a control group and the fact that the examiner who read the bite-wings did not know to which group the participants belonged. The preventive programme in the present study included recurrent education about oral health and tobacco, fluoride varnish application every six month and other regularly performed preventive measures. The effects on caries activity were limited, although fewer individuals in the intervention group showed enamel caries after two years than in the control group. Regarding dentin caries, no significant differences were observed. Caries incidence was lower in the intervention group, although the difference was not statistically significant (p = 0.10) and the preventive fraction was 50%. Because the deviation in terms of DSa values was greater than calculated in the power assessment, a larger sample would have been needed to obtain significant differences. These findings are in line with previous studies by Moberg Sköld et al (2005) and two systematic reviews (Marinho et al, 2002; Petersson et al, 2004), which have shown a caries reduction of 30%–70% in fluoride varnish programmes. The effect on enamel but not on dentin caries corresponds well with previous observations reporting that enamel lesions accounted for more than 90% of caries reduction (Moberg Sköld et al, 2005). One explanation for the somewhat lower reduction in the present study might be that the intervention period was only 24 months compared with 36 months in the study by Moberg Sköld et al (2005). Another explanation could be that the caries prevalence in both groups was already low at
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baseline, which makes it difficult to achieve further improvements. In addition, caries today progresses relatively slowly, and therefore it is logical to expect that new caries lesions in the present study would be found in the outer half of the enamel. Even if the study period had been three years or more, it might not have shown a reduction in dentin caries. The fact that an effect on enamel caries was obtained strengthens the case for fluoride varnish as a useful preventive measure. However, other fluoride varnish programmes have reported no preventive effect in the permanent dentition of children aged 6–8 years who were followed up for up for two years after fluoride had been applied in the schools (Hardman et al, 2007, Milsom et al, 2011). Already at the study’s start, knowledge and attitudes in many areas were favourable among participants. Almost all participants stated that their teeth were important and significantly more adolescents in the intervention group knew that toothbrushing should be carried out twice a day. This is positive and in line with other studies carried out recently in Sweden (Hedman et al, 2006; Jensen et al, 2012). However, only a few participants could explain caries and periodontitis. After two years, significantly more individuals in the intervention group were able to answer the question ‘what does caries mean?’ correctly. In addition, almost twice as many in the intervention group (although not statistically significant due to small group size and low spread) knew what periodontitis meant. Adolescents in the intervention group also had better knowledge about the recommended toothbrushing frequency and the effects of fluoridated toothpaste. In fact, the participants in the intervention group consistently displayed more knowledge about oral health than did the participants in the control group. Knowledge about caries related to dietary habits was limited before the study started, but improved in both groups during the study period. One explanation for the improvement among participants might be that improved knowledge is attributable to the fact that the children simply grew older, as described in other studies (Hedman et al, 2006, Tolvanen et al, 2009). Concerning attitudes toward tobacco, no differences between the groups could be seen after two years. Approximately half of the participants in both groups did not see themselves as future smokers/ snuffers, a observation also reported in other studies (Nilsson et al, 2006; Hedman et al, 2010). Caries is unevenly distributed in the Swedish population. Two different strategies to prevent car-
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ies may be used, population-based and individualbased. High-risk individuals are, however, difficult to identify and reach using a preventive message; it is also difficult to obtain compliance (Hausen, 2004). In addition, since very few individuals in Sweden suffer from severe caries problems, the greatest number of carious lesions will be found among the population with low and medium risk (Rose, 2001; Marthaler, 2004). School-based oral health programmes address all adolescents and adolescents at the highest risk of oral diseases tend to benefit the most from preventive measures. A relationship between knowledge, attitudes and behaviour among schoolchildren has been described, but it has also been shown that children are ready to assimilate new knowledge and attitudes and change their behaviour during different periods in life. Thus, it is important that the promotion be prolonged and not just implemented as a time-limited campaign (Tolvanen et al, 2010). Other advantages of an oral health intervention programme in school, as in the present study, are that the implementation of dental care is more efficient from the perspectives of the adolescents and dental personnel alike. Adolescents save time by eliminating trips to the dental clinic and those with the highest risk have a greater number of preventive measures performed. Schools may provide arenas for oral health care and services (WHO, 2003) and can be useful sources for improving oral health among adolescents in a population. Schools also have a responsibility for child and adolescent health (Tones and Tilford, 2001). Health intervention programmes in schools should include components directed towards both the individual and the school environment (Sellström and Bremberg, 2006). When the individual meets the dental hygienist at school instead of the clinic, it is easier to leave the role of the patient to focus on factors of daily living habits and health promotion. Health promotion should include cooperation and a common understanding of health messages among health workers, educators and students. Therefore, the dental hygienist who is trained to support people on health issues may serve as a ‘bridge’ between different school groups to motivate those who want to promote adolescent health.
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CONCLUSION In conclusion, the two-year school-based oral health programme influenced the prevalence of enamel caries and showed some positive changes in knowledge about oral health among the adolescents. In addition, the adolescents themselves described the programme as positive and reported that the presence of a dental hygienist in school would improve their oral health.
ACKNOWLEDGEMENTS We thank the dental hygienists Marie Lindén and Carina Landh for their skillful implementation of the oral health programme, and the dentist Ulla Thörnblom for evaluating the radiographs. We also thank Lisa Wernroth at Uppsala Clinic Research (UCR) for her statistical analysis. Finally, the authors would like to thank Uppsala County and Public Dental Health for financial support.
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