Excerpts

A collaborative project involving:

Republic of Ireland

The Department of Health and Children
Health Services Executive, formerly the health boards:
East Coast Area
Midland Area
Mid Western Area
North Eastern Area
Northern Area
North Western Area
South Eastern Area
Southern Area
South Western Area
Western Area

Northern Ireland

The Department of Health Social Services and Public Safety
Eastern Board
Northern Board
Southern Board
Western Board

WHO Collaborating Centre for Oral Health Services Research University

College Cork
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Executive Summary

Highlight

• Since 1964, water supplies in the Republic of Ireland (RoI) have been adjusted to 0.8 to 1.0 parts per million (ppm) fluoride. Currently 71% of the population receive fluoridated domestic water supplies.

• In RoI, decay levels are lower among children with  fluoridateddomestic water supplies than they are among those with no domestic water fluoridation.

• Decay levels are lower among children who get fluoride in their water supply in RoI than they are among children in Northern Ireland (NI, no water fluoridation).

• Although decay levels are higher amongst the less well off, disadvantage does not account for the difference seen between flouridated and non flouridated areas. Fluoridation is effective in both disadvantaged and non disadvantaged groups.

• The prevalence of dental fluorosis (most commonly seen as paper white patches or fine white lines on the tooth enamel) is higher amongst children and adolescents with fluoridated water supplies.

• Despite the effectiveness of water fluoridation and fluoride toothpastes, there is little cause for complacency since tooth decay continues to be a very common disease. For example by age 15, 73% of adolescents with fluoridated water supplies in RoI already have decay in their permanent teeth, this compares with 81% in non fluoridated NI.

• Children in RoI have amongst the highest frequency of consumption of foods and drinks sweetened with sugar when compared with 34 other countries (WHO). Given their unfavourable dietary habits and average or below average frequency of brushing (WHO), water fluoridation continues to be an important preventive agent for the control of dental decay levels in Ireland.

• The factors associated with variation in decay levels amongst 15 year-old adolescents in RoI were fluoridation status, parents’ occupational status, frequency of tooth brushing, method of rinsing after tooth brushing and frequency of snacking.

• In NI, there were two factors found to be associated with varying decay levels amongst 15-year-old adolescents, these were parents’ occupational status and amount of toothpaste used when brushing.

• The level of oral hygiene was judged to be unsatisfactory for the majority of children in RoI; this variable was not measured in NI.

• The percentage of 15-year-olds who were under orthodontic treatment or had completed treatment rose from 14% in 1984 to 23% in 2002 in RoI.

• Dependants of medical card holders were less likely to have had orthodontic treatment than those without medical cards (17% vs 26%).

• Amongst 15-year-olds, 22% of those in RoI had trauma to their anterior teeth, compared with 14% in NI. A high proportion of this trauma to anterior teeth remains untreated in RoI.

• In RoI, one in five 12-year-old children, and one in three 15-year old adolescents, had tooth wear exposing dentine on at least one anterior permanent tooth.

• In RoI, 46% of parents were ‘very satisfied’ and 37% were ‘satisfied’ with the dental service provided to their children, 4% of parents were either ‘dissatisfied’ or ‘very dissatisfied’ with the service. In NI, almost all the parents completing the questionnaire were either ‘very satisfied’ (69%) or ‘satisfied’ (29%) with the service provided.

Summary

Since the implementation in 1964 of the Health (Fluoridation of Water Supplies) Act 1960, water supplies in RoI have been adjusted to 0.8 to 1.0 parts per million (ppm) fluoride. Currently 71% of the population of RoI receive fluoridated domestic water supplies. Results of a National Survey of children’s and adolescents’ oral health carried out in 1984 showed that there had been a major decline in dental caries levels both in fluoridated and non fluoridated areas since the pre-fluoridation surveys conducted between 1961 and 1963. Regional oral health surveys carried out in the 1990s indicated a continuing decline in dental caries levels amongst 5-, 8-, 12- and 15-year-old children and adolescents in RoI.

The health strategy in Ireland has placed great emphasis on the collection of quality information on health and its determinants, for health policy planning and evaluation. This North South survey of children’s oral health provides extensive data for representative samples totaling 19,963 children and adolescents on a variety of oral diseases, conditions and related parameters. The data are nationally and internationally comparable and provide a basis for planning and evaluating oral health policy in Ireland.

A critique of many studies of the effectiveness of water fluoridation was their failure to control for confounding factors. Socio economic factors are important variables to take into account when comparing caries levels amongst different communities. Thus, the survey was designed to compare the prevalence of caries between child and adolescent residents in fluoridated and non fluoridated communities in RoI whilst controlling for disadvantage (medical card ownership by child or parents). It also reports the changes in caries levels over time in RoI and reports changes in levels of dental fluorosis between 1984 and 2002.

The specific aims of the survey as set out in the protocol were:

• To measure levels of oral health in children and adolescents in Ireland in 2002, and to compare these data with local surveys conducted in the 1990s, national surveys conducted in 1984 and 1961–‘63, and with data from international surveys.

• To provide a standardised up-to-date database on the oral health of children and adolescents in Ireland.

• To provide information on the oral health gain in children and adolescents since the last national and local surveys.

• To examine the relationship between water fluoridation and dental caries whilst controlling or age group, gender, behavioural aspects and medical card ownership.

• To assess oral health knowledge, attitudes and behaviour amongst children and adolescents, and to link these with oral health status.

• To compare the level of oral health of children attending schools designated ‘special needs’ by the Department of Education and Science with those of the general population (reported separately).

• To assess the perceived availability, accessibility and acceptability of the oral health services to children and adolescents with special needs and to their parents (reported separately).

• To provide information for the evaluation and future planning of oral health services in Ireland.

• To explore the relationship between medical card ownership and oral health.

The study was a cross sectional oral health survey of a representative, random, stratified sample of 5-, 8-, 12- and 15-year old children and adolescents in RoI and NI. Internationally comparable standardised examination criteria were used to record the prevalence and level of dental caries, enamel opacities (including fluorosis), oral hygiene, orthodontic treatment need, trauma and tooth wear. Questionnaires were also completed by 15-year-olds and parents of 8-year-olds. The questions were set to ascertain the children and adolescents’ oral health attitudes and behaviour and the perceived a vailability, accessibility and acceptability of oral health services.

The survey shows that decay levels are much lower in 2002 than they were in 1984. Decay levels are lower among children with fluoridated domestic water supplies. Although decay levels are higher amongst the less well off,disadvantage does not account for the difference seen between flouridated and non flouridated areas. In contrast to many other health promotion activities,which are ineffective among the less well off, water fluoridation prevents dental decay across the social divide.

Whilst decay levels are lower, the prevalence of dental fluorosis is higher amongst children and adolescents with fluoridated water supplies. Comparisons with 1984 data show an increase in the prevalence of fluorosis since that time. Enamel fluorosis has been defined as a “dose-response effect caused by excess fluoride ingestion during the pre-eruptive development of teeth”. This change in the enamel surface is characterized by an altered appearance, ranging from the more common fine white lines or patches to the less frequently occurring hypoplasia, pitting of the enamel surface and a change in tooth morphology in more severe forms. As fluoride has beneficial effects, the extent to which enamel fluorosis is considered by a population to be a public health issue will be best evaluated by offsetting the benefits against the risks. The risks associated with dental decay are that it may result in the loss of teeth, is costly to treat, can be aesthetically disfiguring, and can be associated with a degree of pain. In young children, decay may give rise to the need for general anaesthesia for treatment. Fluoride can reduce dental decay and a certain level of enamel fluorosis may enhance the appearance of teeth. The magnitude of concern that a population of people may have for greater (more severe) levels of enamel fluorosis must be weighed against the magnitude of concern that may be had for a certain level of tooth decay. Research is currently underway to assess the cosmetic impact of mild enamel fluorosis in an Irish context. This work is being carried out by the Oral Health Services Research Centre in University College Cork and is funded by the Irish Health Research Board.

The relative contribution of fluoride toothpastes and water fluoridation to enamel fluorosis in Ireland should be studied further. Recent research suggests a significant relationship between patterns of toothpaste usage in infancy and prevalence of fluorosis at age eight years amongst children in counties Sligo and Leitrim. These findings support those of international research, which indicate that early use of fluoride toothpaste in infants leads to excessive ingestion and absorption of fluoride at a time when the enamel of the permanent teeth is forming, leading to fluorosis of the permanent incisor teeth. A recent review of water fluoridation in Ireland,‘The Forum on Water Fluoridation 2002’, was commissioned by the Minister for Health. The report of the review group made recommendations regarding the rational use of fluoride toothpaste and the reduction of the level of fluoride in the water supplies. It is anticipated that adoption of the recommendations will minimize the occurrence of dental fluorosis and at the same time maintain the important caries preventive benefits experienced to date. There is a need for constant monitoring of dental fluorosis in Ireland.

Levels of dental decay and enamel fluorosis among children and adolescents in the fluoridated RoI are also compared with those in the non fluoridated NI. Caries levels are lower among children who get fluoride in their water supply in RoI than they are among children with non fluoridated water supplies in RoI and NI.

Despite the overall decline in decay levels over the last three decades,there is little cause for complacency since tooth decay continues to be a very common childhood disease. For example by age 15, 73% of adolescents with fluoridated water supplies in RoI already have decay in their permanent teeth, this compares with 81% in non fluoridated NI. A recentWHO study revealed that Ireland was amongst the worst of 35 countries studied when it came to child and adolescent consumption of sweets and soft drinks and tooth brushing habits. For example, of the 35 countries surveyed, Ireland ranked second for daily sweet consumption at age 13. In the present study, over half of the 8-year-olds and approximately two thirds of 15-year-olds in RoI and NI consumed sweet snacks twice a day or more often. The present study also showed that there has been a substantial increase in the frequency of snacking among 8- and 15-year-olds in RoI since 1984. In theWHO study, tooth brushing frequency (twice daily or more often) was lower than the 35 country average for girls (67% compared to 73%) and similar to the average for boys (54% compared with 52%). In the study described in this report, frequency of tooth brushing was higher in NI than in RoI. In RoI, the frequency has increased since 1984. In NI, 92% of 8-year-olds and 91% of 15-year-olds reported visiting the dentist at least every 12 months. In RoI, the percentage is much lower at 42% for 8-year-olds and 50% for 15-year-olds. In RoI, 21% of 8- year-olds and 18% of 15-year-olds had never been to a dentist compared to 1% and 2%, respectively, in NI. Given these relatively unfavorable habits, the level of dental decay in RoI is remarkably low; this is likely to be due to the fluoridation of water supplies. This is evidenced by the higher levels of decay among those in non fluoridated areas of RoI and NI, where the dietary habits are similar but there is no water fluoridation…