Tooth Fillings & Behavior- Why Correlation is NOT Causation

There has been a recent release of a large quantity of articles suggesting a connection between children who have teeth filled with composite fillings (the white kind) and negative behaviors. Most are citing BPA (Bisphenol A) as the chemical responsible for altering children’s emotional and behavioral output.

But there’s a CORRELATION…

This is one of those moments where I thank my lucky stars that every single professor I had felt compelled to remind us that correlation is not the same as causation. At the risk of sounding overly academic, just because two things share something in common, does not mean they are related. If most names in the obituaries contains the letter ‘a,’ there is a correlation. Those individuals are (one would assume) not deceased due to any particular letter in their name; however, so there is not a causal relationship. The letter ‘a’ did not lead to their deaths, but it would show up as a statistical similarity. The missing information is that the letter ‘a’ is prevalent in all names, so it will then be included in a high percentage of names of people who are deceased as well.

This Study

Researchers found that children with multiple composite teeth fillings scored consistently worse on a behavior measure than children with no fillings. Approximately 500 children were evaluated after being assigned to different treatment groups based on type of fillings. BPA has been linked to other health concerns in the past, making it appear to be related in this case. The current study suggests that fillings break down over time due to chewing and release bisGMA, which contains BPA.Changes in behavior reported, by parents, were small and no initial behavior evaluation occurred. As more than half of all American children will have a filling by the time they are in second grade, parents are left wondering what the safest dental fillings are for their children. The basic summary of recommendations is to avoid cavities by teaching children to practice good dental hygiene.

So, What’s this Mean?

Here’s the “Scooby Doo” (or “short version”- if you aren’t in the second grade and don’t know what that means). You can make your own decisions by reviewing the study abstract here. An association was found between exposure to white fillings and psychological ‘impairment’ are defined in the study by scores on the Child Behavior Check List (CBCL). The CBCL is a tool often used to identify behavioral and mental health concerns. However, one study alone cannot identify the why of this association. So, we’re back to the example of ‘death-by-letter-a.’ It is entirely possible that children who are sensitive to sugar have more irritable temperaments (‘sugar crash’ anyone?). What else is connected to sugar consumption? Cavities. What are most cavities filled with? White filling, as it matches the teeth. There’s no evidence to support my (non-dental-trained) hypothesis, but there’s also no evidence to show that the BPA is truly causing the behavioral concerns.

Other randomly generated explanations:

• Fussy children are more likely to be bribed with candy making them more susceptible to cavities.
• Children who are stressed (due to temperament) are more likely to grind their teeth, resulting in increased wear-and-tear on teeth, more cavities, and more released filling matter.
• Children (in general) are likely to tantrum to avoid non-preferred tasks (thus, making them stand out on the CBCL AND avoid tooth-brushing).

Overall, with only 1 study, there may well be an association between fillings and behavior. It may be something to worry about, but it may also simply be a commonality, not a cause. As the researchers of the study suggest, more information and data-driven research is needed to evaluate their findings.

In the meantime, get behavioral support if you need it, and teach your child to brush and floss!