Associations Between Tap/Bottled Water Consumption And Caries In Adolescents

Objectives:

Although there have been substantial declines in dental caries among schoolchildren, dental caries is still a common and costly problem. While water fluoridation has been recognized as an effective method of reducing dental caries, increasing use of low-fluoride bottled water may limit its effectiveness. This study evaluated associations between consumption of tap/bottled water and caries increments among adolescents from age 13 to 17.

Methods:

Iowa Fluoride Study participants (N=215) had caries examinations at approximately ages 13 and 17 by three calibrated examiners. Caries assessments (D2F) were recorded for each tooth surface, with exams linked by subject, tooth and surface to determine surface-level D2F increments. Total smooth surface and pit/fissure increments were analyzed separately, and combined (total D2FS). Data on water sources and daily tap/bottled water consumption amounts were collected by questionnaire twice yearly and averaged over four years. Documented water fluoride content from municipal sources and assay of private sources were used to obtain subject-specific tap/bottled water fluoride levels. Descriptive statistics, Spearman correlation, and logistic and negative binomial regression were used.

Results:

Of the 215 participants (53.5% female and 85.6% home incomes>$40,000), 51.2% never drank bottled water.  Average daily intake of tap and bottled water were 0.62±0.38L and 0.13±0.19L, respectively. Mean fluoride level was 0.77±0.36ppm for tap water and 0.10±0.08ppm for bottled water. Substantial caries experience was found, with 15.3% of subjects showing increased D2FS on smooth surfaces, 49.8% on pit/fissure surfaces, and 52.6% overall. Although no significant associations were found between caries incidence (yes/no) and tap or bottled water consumption, significant inverse relationships were found between tap water intake and D2FS increments for pit/fissure surfaces (p=0.0065) and all surfaces (p=0.0041).

Conclusions:

Higher intakes of tap water are associated with reduced caries increments (D2FS), but there was no evidence that increased caries incidence is related to bottled water consumption.