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.

Fluoridation cessation and oral health equity: a 7-year post-cessation study of Grade 2 schoolchildren in Alberta, Canada.

OBJECTIVE: Community water fluoridation, because of its universal scope and passive mechanism of uptake, is one component of a multifaceted approach to promoting equity in dental health. The objective of this study was to examine social inequities in children's dental health in the Canadian cities of Calgary (fluoridation cessation in 2011) and Edmonton (still fluoridated). METHODS: We analyzed data from surveys of population-based samples of Grade 2 (approx. age 7) children in Calgary in 2009/2010 (pre-cessation; n=557) and in both Calgary and Edmonton in 2013/2014 (Calgary, n=3230; Edmonton, n=2304) and 2018/2019 (Calgary, n=2649; Edmonton, n=2600) (post-cessation). We estimated associations between several socioeconomic indicators and dental caries indicators (i.e., dental caries experience [deft, DMFT] and untreated decay in two or more teeth [untreated decay]) using zero-inflated Poisson, binary logistic regression, and the concentration index of inequality. We compared those associations over time (between survey waves) and between cities at post-cessation. RESULTS: Persistent social inequities in deft and untreated decay were evident; for example, having no dental insurance was significantly associated with higher odds of untreated decay across city and survey wave. In most (but not all) cases, differences between cities and survey waves were consistent with an adverse effect of fluoridation cessation on dental health inequities. For example, the association between no dental insurance and higher odds of untreated decay in Calgary was greater in 2018/2019 (later post-cessation) than in 2009/2010 (pre-cessation; odds ratio [OR] for comparison of coefficients = 1.89 [1.36-2.63], p<0.001) and 2013/2014 (early post-cessation; OR for comparison of coefficients = 1.67 [1.22-2.28], p=0.001); that same association in 2018/2019 was greater in Calgary (fluoridation cessation) than in Edmonton (still fluoridated) (OR for comparison of coefficients = 1.44 [1.03-2.02], p=0.033). CONCLUSION: Social inequities in dental caries were present in both Calgary and Edmonton. Those inequities tended to be worse in Calgary where fluoridation was ceased. Our findings may be relevant to other settings where income inequality is high, dental services are costly, and dental public health infrastructure is limited.

RéSUMé: OBJECTIF: En raison de sa portée universelle et de son mécanisme de réception passif, la fluoration de l'eau des communautés s'inscrit dans une démarche multidimensionnelle de promotion de l'équité en santé dentaire. Notre étude visait à examiner les iniquités sociales en santé dentaire chez les enfants dans les villes canadiennes de Calgary (où la fluoration a cessé en 2011) et d'Edmonton (où l'eau est encore enrichie en fluor). MéTHODE: Nous avons analysé les données d'enquêtes menées auprès d'échantillons populationnels d'élèves de 2e année (environ 7 ans) à Calgary en 2009-2010 (avant l'arrêt; n = 557), et à Calgary et Edmonton en 2013-2014 (Calgary, n = 3 230; Edmonton, n = 2 304) et en 2018-2019 (Calgary, n = 2 649; Edmonton, n = 2 600) (après l'arrêt). Nous avons estimé les associations entre plusieurs indicateurs socioéconomiques et indicateurs de caries dentaires (c.-à-d. l'expérience de caries dentaires [dceo, DCMO] et de dégradation non traitée dans deux dents ou plus [dégradation non traitée]) à l'aide de la régression de Poisson à surreprésentation de zéros, de la régression logistique binaire et de l'indice de concentration des inégalités. Nous avons comparé ces associations dans le temps (entre les cycles de l'enquête) et entre les deux villes après l'arrêt de la fluoration. RéSULTATS: Des iniquités sociales persistantes selon l'indice dceo [dents cariées, extraites et obturées] et la dégradation non traitée étaient manifestes; par exemple, l'absence d'assurance dentaire présentait une corrélation significative avec une probabilité accrue de dégradation non traitée d'une ville à l'autre et d'un cycle à l'autre de l'enquête. Dans la plupart des cas (mais pas tous), les différences entre les villes et entre les cycles de l'enquête correspondaient à un effet indésirable de l'arrêt de la fluoration sur les iniquités en santé dentaire. Par exemple, l'association entre l'absence d'assurance dentaire et la probabilité accrue de dégradation non traitée à Calgary était plus importante en 2018-2019 (longtemps après l'arrêt) qu'en 2009-2010 (avant l'arrêt; rapport de cotes [RC] pour comparaison des coefficients = 1,89 [1,36-2,63], p < 0,001) et qu'en 2013-2014 (peu après l'arrêt; RC pour comparaison des coefficients = 1,67 [1,22-2,28], p = 0,001); cette même association en 2018-2019 était plus importante à Calgary (où la fluoration a cessé) qu'à Edmonton (où l'eau est encore enrichie en fluor) (RC pour comparaison des coefficients = 1,44 [1,03-2,02], p = 0,033). CONCLUSION: Des iniquités sociales relativement aux caries dentaires étaient présentes tant à Calgary qu'à Edmonton. Ces iniquités avaient tendance à être plus importantes à Calgary, où la fluoration a cessé. Nos constatations pourraient être pertinentes dans les autres endroits où l'inégalité des revenus est élevée, où les soins dentaires coûtent cher et où les infrastructures en santé publique dentaire sont limitées.

Fluoridation cessation and children's dental caries: A 7-year follow-up evaluation of Grade 2 schoolchildren in Calgary and Edmonton, Canada.

OBJECTIVES: We examined the effect of fluoridation cessation on children's dental caries experience in the Canadian cities of Calgary (cessation in 2011) and Edmonton (still fluoridated). METHODS: We used a pre-post cross-sectional design with comparison group. We studied Grade 2 schoolchildren (approximately 7 years old) 7-8 years after fluoridation cessation in Calgary, thus capturing children born after cessation occurred. Data collection included a dental examination conducted in school by calibrated dental hygienists, a questionnaire completed by parents, and fingernail clippings for a small subsample. Our overall analytic approach was twofold. We first examined differences in dental caries experience (deft and DMFT, and smooth surface caries based on defs and DMFS) between Calgary and Edmonton and over time (comparing 2018/2019 data to pre-cessation and early post-cessation surveys in our setting). Second, we evaluated whether differences were likely to reflect fluoridation cessation in Calgary, rather than other factors. RESULTS: The prevalence of caries in the primary dentition was significantly higher (P < .05) in Calgary (fluoridation cessation) than in Edmonton (still fluoridated). For example, crude deft prevalence in 2018/2019 was 64.8% (95% CI 62.3-67.3), n = 2649 in Calgary and 55.1% (95% CI 52.3-57.8), n = 2600 in Edmonton. These differences were consistent and robust: they persisted with adjustment for potential confounders and in the subset of respondents who were lifelong residents and reported usually drinking tap water; they had widened over time since cessation; and they were corroborated by assessments of dental fluorosis and estimates of total fluoride intake from fingernail clippings. Findings for permanent teeth were less consistent, which likely reflects that 7-year-olds have not had the time to accumulate enough permanent dentition caries experience for differences to have become apparent. CONCLUSIONS: Our findings are consistent with an adverse impact of fluoridation cessation on children's dental health in Calgary and point to the need for universal, publicly funded prevention activities-including but not limited to fluoridation.

Ethnic disparities in children's oral health: findings from a population-based survey of grade 1 and 2 schoolchildren in Alberta, Canada.

BACKGROUND: Although oral health has improved remarkably in recent decades, not all populations have benefited equally. Ethnic identity, and in particular visible minority status, has been identified as an important risk factor for poor oral health. Canadian research on ethnic disparities in oral health is extremely limited. The aim of this study was to examine ethnic disparities in oral health outcomes and to assess the extent to which ethnic disparities could be accounted for by demographic, socioeconomic and caries-related behavioral factors, among a population-based sample of grade 1 and 2 schoolchildren (age range: 5-8 years) in Alberta, Canada. METHODS: A dental survey (administered during 2013-14) included a mouth examination and parent questionnaire. Oral health outcomes included: 1) percentage of children with dental caries; 2) number of decayed, extracted/missing (due to caries) and filled teeth; 3) percentage of children with two or more teeth with untreated caries; and 4) percentage of children with parental-ratings of fair or poor oral health. We used multivariable regression analysis to examine ethnic disparities in oral health, adjusting for demographic, socioeconomic and caries-related behavioral variables. RESULTS: We observed significant ethnic disparities in children's oral health. Most visible minority groups, particularly Filipino and Arab, as well as Indigenous children, were more likely to have worse oral health than White populations. In particular, Filipino children had an almost 5-fold higher odds of having severe untreated dental problems (2 or more teeth with untreated caries) than White children. Adjustment for demographic, socioeconomic, and caries-related behavior variables attenuated but did not eliminate ethnic disparities in oral health, with the exception of Latin American children whose outcomes did not differ significantly from White populations after adjustment. CONCLUSIONS: Significant ethnic disparities in oral health exist in Alberta, Canada, even when adjusting for demographic, socioeconomic and caries-related behavioral factors, with Filipino, Arab, and Indigenous children being the most affected.

Measuring the short-term impact of fluoridation cessation on dental caries in Grade 2 children using tooth surface indices.

OBJECTIVES: To examine the short-term impact of fluoridation cessation on children's caries experience measured by tooth surfaces. If there is an adverse short-term effect of cessation, it should be apparent when we focus on smooth tooth surfaces, where fluoride is most likely to have an impact for the age group and time frame considered in this study. METHODS: We examined data from population-based samples of school children (Grade 2) in two similar cities in the province of Alberta, Canada: Calgary, where cessation occurred in May 2011 and Edmonton where fluoridation remains in place. We analysed change over time (2004/2005 to 2013/2014) in summary data for primary (defs) and permanent (DMFS) teeth for Calgary and Edmonton, for all tooth surfaces and smooth surfaces only. We also considered, for 2013/2014 only, the exposed subsample defined as lifelong residents who reported usually drinking tap water. RESULTS: We observed, across the full sample, an increase in primary tooth decay (mean defs - all surfaces and smooth surfaces) in both cities, but the magnitude of the increase was greater in Calgary (F-cessation) than in Edmonton (F-continued). For permanent tooth decay, when focusing on smooth surfaces among those affected (those with DMFS>0), we observed a non-significant trend towards an increase in Calgary (F-cessation) that was not apparent in Edmonton (F-continued). CONCLUSIONS: Trends observed for primary teeth were consistent with an adverse effect of fluoridation cessation on children's tooth decay, 2.5-3 years post-cessation. Trends for permanent teeth hinted at early indication of an adverse effect. It is important that future data collection efforts in the two cities be undertaken, to permit continued monitoring of these trends.

Equity in children's dental caries before and after cessation of community water fluoridation: differential impact by dental insurance status and geographic material deprivation.

BACKGROUND: One of the main arguments made in favor of community water fluoridation is that it is equitable in its impact on dental caries (i.e., helps to offset inequities in dental caries). Although an equitable effect of fluoridation has been demonstrated in cross-sectional studies, it has not been studied in the context of cessation of community water fluoridation (CWF). The objective of this study was to compare the socio-economic patterns of children's dental caries (tooth decay) in Calgary, Canada, in 2009/10 when CWF was in place, and in 2013/14, after it had been discontinued. METHODS: We analyzed data from population-based samples of schoolchildren (grade 2) in 2009/10 and 2013/14. Data on dental caries (decayed, missing, and filled primary and permanent teeth) were gathered via open mouth exams conducted in schools by registered dental hygienists. We examined the association between dental caries and 1) presence/absence of dental insurance and 2) small area index of material deprivation, using Poisson (zero-inflated) and logistic regression, for both time points separately. For small-area material deprivation at each time point, we also computed the concentration index of inequality for each outcome variable. RESULTS: Statistically significant inequities by dental insurance status and by small area material deprivation were more apparent in 2013/14 than in 2009/10. CONCLUSIONS: Results are consistent with increasing inequities in dental caries following cessation of CWF. However, further research is needed to 1) confirm the effects in a study that includes a comparison community, and 2) explore possible alternative reasons for the findings, including changes in treatment and preventive programming.