One of the recurrent scenarios in medical or scientific research is when elements of the body seem to interact but no one is quite certain how or why. The waters can get further muddied when people try and spin small or seemingly insignificant results into larger declarations of fact. This situation appears to be at play in a recent Spanish study that tries to tie a person’s bad bite to possible issues with postural control. The idea that dental occlusion could influence balance is not necessarily implausible, but the claim that this study represents “conclusive research” as the authors claim is hard to believe.
In Brief: Terminology
- Postural Control: Refers to how well a person can achieve and hold their balance during various types of activities and postures
- Dental Occlusion: Contact between the upper and lower teeth and how aligned they are when at rest, chewing, etc. Natural alignment as well as gaps between the teeth, crossbites, missing teeth, and so on, can all be involved in this
Tying Imperfect Bites to Balance
Due to the way the nerves and such within the jaw and face are arranged and connected, problems with a person’s bite can end up causing issues elsewhere. This is why, for instance, people who grind their teeth can experience headaches or eye pain. There is a reciprocal relationship in particular between the trigeminal nerve (tied to chewing) and the vestibular nucleus (involved in balance). Therefore, a bite or jaw problem that affects chewing could end up influencing the vestibular nucleus, so the thinking goes.
The study took ten physically active subjects and put them through sets of lower-limb exercises and balance tests on stable and unstable platforms. The idea was to see if there was any difference in balance between opposed types of dental occlusion and whether this influence got stronger or weaker when fatigued. The findings:
- At unstable levels, balance control was better for participants when the jaw was in a neutral (CR, or “central relation”) position
- At a stable level, dental occlusion only showed significance when the person was fatigued
- Under both conditions, performance was worse when the participants were tired
Now, even if these findings are taken as accurate and not subject to the blindingly obvious problem of trying to do this type of analysis on a group of only ten people, there are still problems here:
- Unstable platforms and fatigue are going to contribute to a person’s difficulty with balance but there is no mention of how this was controlled for in the analysis
- No indication that other traits that could affect balance were controlled for
- No description of the type of instability that was observed was given. Are these people toppling over, or just wobbling for half a second?
- No description is given of just how postural control improved, only that it “significantly improved” and some p-values. Over-emphasis on statistical significance but bare mention of actual results is highly suspect
What This Means
Kudos to the researchers for testing posture control on both stable and unstable states, but that’s all that can be given to them. Even if all of their number-crunching was sound, it still wouldn’t matter since ten people for a common trait like a bad bite is too small to be meaningful. Hopefully someone will get inspired by this study to do the research on a more meaningful scale because otherwise it seems pointless. It is most definitely not the “conclusive research” the piece is touted as in its press release, and to try and claim it as so is a staggering level of hyperbole.
Julia-Sanchez, S., et. al., “The influence of dental occlusion on the body balance in unstable platform increases after high intensity exercise,” Neuroscience Letters, 2016; http://dx.doi.org/10.1016/j.neulet.2016.02.003.