I wrote here on how sugar causes cavities, emphasizing how the oral flora influences salivary pH based upon diet.
There’s another piece to that story, though. Just like the rest of your body, your teeth have a built-in system to self-heal. Here’s how it works.
The Dentinal Fluid Transport System (DFTS)
Most of the body gets nourished directly by the blood, but it is believed (though apparently still debatable) that the teeth receive their nutrients necessary for metabolism and healing from their own lymphatic system. The assumption is that the dental lymph gets pumped from the pulp chamber via hydrostatic pressure, through the tubules in the dentine, and all the way out to the enamel. The pulp also contains stem cells that can differentiate into the cell type needed to repair any damage the tooth may incur—these too can be pumped out from the pulp through the tubules via the dental lymph.
The tubules in the dentine are just tubules, though. They don’t have valves, like blood vessels do, or nodes (we don’t think anyway), like the rest of the lymphatic system does. What this means is, flow can go from inside out, with all of the attendant nutrients from the blood, or from outside in… which is where problems can occur.
The Parotid Hormone and the DFTS
The appropriate inside-out flow of the dental lymph is regulated by parotid hormone, signaled first from the hypothalamus and released from the pituitary. Parotid hormone, in turn, triggers the parotid gland to regulate the DFTS by increasing the pH of the saliva. This is apparently a different mechanism than the production of saliva itself, which also comes from the parotid gland in part.
In other words, an alkaline pH (internally generated or otherwise) is critical for oral health. This is what keeps the dental lymph flowing from the inside out.
The saliva itself also helps to nourish the teeth. In a healthy, alkaline environment, the dental lymph wells up on the inside of the teeth, while the outside is bathed in nutrient-rich saliva at the same time.
Sugar, Insulin, and the DFTS
We all know that sugar can cause cavities, in part because they feed bad bacteria.
But sugar is also inherently acidic. Saliva can counter this, and in fact it does so with more gusto in the presence of an acid in order to restore homeostasis.
But homeostatic systems can only overcome so much. Just as in the blood buffering system, eventually there will be collateral damage somewhere. (I found some speculation that this might take the form of parotid gland atrophy. This would make perfect sense, though I couldn’t find any studies to back it up.)
Aside from the theory that the acid itself eats away at the enamel, there’s a bigger potential problem: as mentioned above, the DFTS requires an alkaline pH in order to flow from inside out. Without the pressure from this system, reversing the flow to outside in could a) allow opportunistic bacteria access to the tooth, and b) inhibit delivery of repair mechanisms to the site of injury.
How to Optimize Dental Healing
Clearly, pH is important—and so an alkaline diet helps to keep the saliva in the right range. It takes the stress off the parotid gland.
Brushing your teeth with baking soda is also helpful to this end, and for the same reason.
It’s also important to make sure you have adequate amounts of the minerals necessary for dental repair, both from the saliva and from the dental lymph. The biggest two are calcium and phosphorus, and primarily the latter, as the parotid gland is responsible for secreting phosphorus into saliva, whereas the submandibular gland is the one that releases calcium. Also, lower salivary phosphorus levels appear to be particularly correlated with increased dental caries. This animal study shows that phosphorus supplementation protects dentine from sugar damage, but only in those animals with an intact parotid gland. In those whose parotid glands were removed, increased phosphorus made no difference.
For both pH and adequate nutrition then, a whole foods diet and a good multivitamin are a good place to start. Phosphorus in particular is high in chicken, turkey, pork, fish, dairy, nuts, seeds, legumes, and whole grains. However, in nuts, seeds, whole grains, and legumes, it is bound in phytic acid which is indigestible to humans. So it’s a good idea to soak these plant based sources until they sprout in order to break down phytic acid, helping to release nutrients for better absorption.
Antacids also deplete phosphorus, so if you’ve been using them and you’re concerned about dental health, it’s a good idea to stop. (Instead, I’d suggest seeing your holistic health care provider to find the root cause of reflux or heartburn in the first place!)