Abstract
Background: Fluoride is effective at preventing dental caries, however ingesting too much can lead to fluorosis. New Zealand (NZ) has naturally low levels of fluoride in water (~0.15 mg/l). Worldwide, the prevalence of dental caries is lowest in areas with water fluoride concentrations around 0.7 to 1.0 mg/l, which aligns with the recommendations of the NZ Ministry of Health. Currently, only 59 % of the NZ population has access to fluoridated water. There is no data on fluoride intakes for children five years and older, despite oral health being important across the lifespan.
Objective: This study aimed to measure fluoride intakes of nine to 11-year old children living in a fluoridated area and non-fluoridated area of the South Island of New Zealand.
Design: This study aimed to recruit 50 children from Dunedin (fluoridated area) and 50 from the Waitaki region (non-fluoridated area). Children collected a 24-hour diet record and 24-hour urine sample, both undertaken on the same day; with repeat collections of diet records and 24-hour urine samples obtained from a sub-sample. During a home visit, children were asked to follow their usual toothbrushing routine and expectorated toothpaste/saliva was collected to estimate fluoride ingested from toothpaste.
Results: Forty-eight children from Dunedin (fluoridated area) and 16 from the Waitaki region (non-fluoridated area) took part in this study; repeat collections were obtained for 29 children. The mean (SD) for total daily fluoride intake was 1.55 mg/day (0.96) and 1.04 mg/day (0.87) for children living in fluoridated and non-fluoridated areas, respectively, which are below the recommended Adequate Intake of 2 mg/day. The mean (SD) for fluoride ingested from toothpaste was 0.81 mg/day (0.84) for the fluoridated group and 0.69 mg/day (0.85) for the non-fluoridated group, approximately 40 % of the Adequate Intake. No children exceeded the Upper Limit of 10 mg/day. The mean (SD) for daily urinary fluoride excretion was 0.55 mg/day (0.46) for the fluoridated group and 0.23 mg/day (0.15) for the non-fluoridated group, which equates to an excretion of 42 % and 31 % of ingested fluoride, respectively.
Conclusion: New Zealand children aged nine to 11-years are not meeting the recommended optimal level of fluoride intake, irrespective of fluoridation status and may be at increased risk of dental caries.