Fluoride exposure, dental fluorosis and caries in South Australian children

Fluoride use among children involves balancing between protection against caries and risk of fluorosis. Policy guiding fluoride exposures to reduce fluorosis experience may have an adverse effect of increasing caries experience. Objective: To identify appropriate measures to control fluoride exposure by examining associations of changes in fluoride exposure with fluorosis and caries. Methods: A random sample of 9-14-year-old South Australian (SA) children enrolled with SA Dental Service was selected in 2002/2003, stratified by fluoridation status and urban/rural residence. Fluoride exposure history was collected by parental questionnaire. Caries data at age six and eight years were collected from clinic records for 1084 children to calculate deciduous dmfs. One dentist examined 677 children for fluorosis using the Thylsrup and Fejerskov (TF) Index. Data were re-weighted to reflect the child population. Fluorosis case was defined as having a TF score of 2+. Results: Fluorosis and caries experience by fluoride exposure are:

Prevalence of fluorosis (%) Caries (dmfs, SD)
Age 6 Age 8
Total 11.8 1.37 (3.03) 2.38 (4.36)
Exposure to water fluoridation
>50% lifetime \x8614.2 *0.94 (2.34) *1.65 (3.16)
>0&<=50% lifetime 13.2 1.71 (3.43) 3.00 (5.18)
0% lifetime 4.1 2.19 (4.06) 3.53 (5.09)
Age when toothbrushing commenced
<19-month \x8614.3 *1.03 (2.48) *1.85 (3.58)
19-30-month 12.5 1.13 (2.60) 2.32 (3.79)
31+month 7.6 2.04 (4.00) 3.20 (5.81)
Toothpaste fluoride concentration
1000-ppm \x8616.2 1.44 (3.25) 2.30 (4.86)
<550-ppm 6.4 1.36 (2.92) 2.51 (4.31)
Eating/licking toothpaste
Yes \x8615.4 1.36 (2.95) 2.39 (4.01)
No 9.2 1.35 (3.08) 2.37 (4.63)

\x86Chi-square, p<0.05; *ANOVA, p<0.01

Conclusions: Modifying lifetime exposure to water fluoridation to reduce fluorosis could significantly increase caries experience. Use of low concentration fluoride toothpaste and preventing toothpaste eating/licking could reduce fluorosis prevalence without a significant increase in caries. Recommendation regarding appropriate age to commence toothbrushing requires more detailed analyses.

Supported by NHMRC, ADRF, and University of Adelaide.

Do L*, Spencer AJ

Presented at the 83rd General Session and Exhibition of the IADR, 9 – 12 March 2005, Baltimore, USA

Note: * indicates presenter

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