Quantifying Fluoridation Exposure Over Time in Alberta, Canada: Challenges and Implications for Dental Public Health Surveillance.

Background: Community water fluoridation is one component of a multifactorial approach to preventing dental caries. Yet, fluoridation monitoring in Canada has historically been fragmented, and recent national estimates give little indication of trends at the provincial or municipal levels. We aimed to quantify fluoridation exposure trends in Alberta from 1950 to 2018 at both the population and municipal levels. Insights have implications for dental public health surveillance.

Methods: Drawing from various public sources, we compiled a list of all Alberta municipalities, noting type of municipality and annual population count from 1950 to 2018. We recorded fluoridation status (excluding naturally occurring fluoride) by year for each municipality, based on the start and end (if ever) dates. We calculated annual fluoridation exposure at the population level (% of Alberta population exposed) and the municipality level (number of municipalities exposed) to visually assess trends over time.

Results: Population exposure to fluoridation in Alberta generally increased from 1950 to 2010. A sharp drop occurred in 2011, after which exposure fluctuated at around 43-45%. Municipality exposure generally increased from 1958 to 2006 and from 2012 to 2018, except for small declines during 2007-2008 and 2010-2011. Challenges concerning data completeness were considerable.

Conclusion: Our findings illuminate the substantial variation in fluoridation exposure of Albertans over time, and they elucidate the complexities of estimating such exposure. They speak to the value of centralized fluoridation monitoring mechanisms as a key part of dental public health surveillance infrastructure.