CDA Essentials 2017 • Volume 3 • Issue 4

17 Volume 3 Issue 4 | N ews and E vents The other thing to mention is that studies like this do not provide definitive proof of anything. That’s just their nature. They’re observational, they’re complex, and sometimes people are seeking definitive proof and we simply can’t provide that. But this desire to have easy, quick answers has the consequence of information being misconstrued or overly simplified. Do you think lack of scientific literacy is part of the challenge in helping decision makers understand the issue of fluoridation? I do think that’s an important challenge and I think, as researchers, we have a role to play in increasing scientific literacy, although we’re not always very good at it. In our case, we made the decision to publish our work in open access format, which means that it is in the public domain, and to make ourselves available to present or explain the study, if needed. People used your study’s results to argue in favour of, or against, fluoridation, depending on who was interpreting the data. Given the different reasons people have for opposing fluoridation, how important do you think scientific evidence is in the fluoride debates? That was very interesting. We’re well aware that this decision is not just about evidence. I think evidence needs to be part of it, but the available evidence needs to be considered as a whole and to be interpreted fairly and rigorously. City councillors are in a difficult position because they have to juggle all those different factors. Did you read any of the public commentaries from those who were quick to denounce your research, or feel an urge to defend it? Yes, the criticism came very quickly! We read some of it. Some of the comments were fair and what we would expect within the domain of scientific debate. But others were a bit more aggressive and we just weren’t sure of the value of entering into those discussions. McLaren L, Patterson S, Thawer S, Faris P, McNeil D, Potestio M, Shwart L. Measuring the short-term impact of fluoridation cessation on dental caries in Grade 2 children using tooth surface indices. Community Dent Oral Epidemiol. 2016;44(3):274-82. The question : Does removing fluoride from municipal water have a short-term impact on dental caries of children’s tooth surfaces? Study population : Children in Calgary and Edmonton who were in grade 2 in 2004-05 (before fluoride was taken out of municipal water in Calgary) and in 2013-14 (after fluoride was removed in Calgary). Over 5,000 children were included in the study. What was measured : Decayed, extracted (due to caries), and filled primary tooth surfaces (defs) and decayed, missing (due to caries), and filled permanent tooth surfaces (DMFS). Data were analyzed for all tooth surfaces and smooth surfaces only. Results : For primary teeth, in both Calgary and Edmonton there was a statistically significant increase in tooth decay in 2013-14 (after fluoride cessation) compared to 2004-05 (before Calgary removed fluoride from its drinking water). But the increase was significantly greater in Calgary. For example, in Calgary, the number of defs rose, on average, by 3.8 between 2004-05 and 2013-14—the time during which fluoride was removed from city water—whereas in Edmonton, the average increased by 2.1. For all tooth surfaces among permanent teeth, decay decreased (i.e., there was an improvement in oral health) in both Calgary and Edmonton, although the decrease was statistically significant only in Calgary. However, when focusing on smooth surfaces among those affected (those with DMFS > 0), there was a non-significant trend towards an increase in decay in Calgary (after fluoride cessation) that was not apparent in Edmonton. What it means : The authors conclude that for primary teeth, the study results show that removing fluoride from municipal water supplies in Calgary increased tooth decay over the short term (i.e., 2.5 to 3 years after fluoride cessation). Trends for permanent teeth hint at an early indication of an adverse effect, but it will be very important to continue monitoring these trends. The study at a glance