Impact of fluoridation and disadvantage on tooth retention in Ireland

Objectives: To compare the percentage of adults with more than 20 natural teeth according to fluoridation status and disadvantage in the Republic of Ireland.

Methods:

One of the aims of the 2000/'02 national survey of the oral health of Irish adults was to measure the effect of domestic water fluoridation on oral health (Whelton et al: http://www.dohc.ie/publications/oral_health02.html).

A number of outcome measures were utilised to estimate the effect, including the percentage with more than 20 natural teeth present. In a previous presentation in 2004, Whelton et al showed an increase between 1989/'90 and 2000/'02 in the proportion of adults possessing 20+ natural teeth particularly for 35-44-year-olds. Water fluoridation in Ireland commenced in Dublin in 1964 and the majority of the remaining urban communities were fluoridated over the next five years. The 35-44 age group were aged 0-13 years when water fluoridation was introduced in Ireland and were unlikely to have suffered extensive tooth loss before it started. Hence the impact of fluoridation on tooth retention is worth investigating in this age cohort as they were in a position to benefit from fluoridation from an early age.

Results:

The percentage of 35-44-year-old lifetime residents of full-fluoridated communities (n=296) with more than 20 natural teeth was 92.4% compared with 83.2% in the non-fluoridated group (n=176) (p<0.05). In the full-fluoridated group, amongst those categorized as disadvantaged (less well off) (n=69), 78.4% had more than 20 natural teeth, compared with 95.3% in the non-disadvantaged group (n=226) (p<0.05). In the non-fluoridated group, the corresponding figures were 63.2% (n=37) and 88.5% (n=137) (p<0.05).

Conclusions:

There is a greater percentage of 35-44-year-olds possessing more than 20 natural teeth residing in full-fluoridated areas than non-fluoridated areas, regardless of disadvantage status.