“Why me? ”
This is the question dentists hear again and again from patients who brush twice a day, floss daily, eat right, and still seem to get more cavities than everybody else does. It seems unfair, since we all know people who neglect their oral hygiene and never have cavities or any dental problems at all.
“What am I doing wrong?”
The correct answer could be: nothing. It may be that you were born with a greater-than-average vulnerability to tooth decay. A disadvantage, to be sure, but one that can be addressed once it’s recognized.
GENES AND TEETH
Genes influence health tendencies, but don’t totally determine health outcomes. The genes you were born with establish built-in potentials and limits, but the choices you make are what locate you within that range of possibilities. You get your DNA from your parents, but you don’t have to inherit any of their behaviors that invite tooth decay or other dental problems.
Some people are born with more resistance to decay, others with less. Even so, genetic advantages can be “wasted” by neglect of oral hygiene, and we can make up for our hereditary weaknesses through education, attention, and care.
Some of the traits passed genetically from parent to child play a pretty straightforward role in oral health. A good example is enamel. Research has shown that a gene known to determine the strength of hair shafts (go figure!) also controls the hardness of tooth enamel. Harder enamel is more resistant to erosion, soft enamel is less so. Other things being equal, a person with softer enamel will likely have more decay and more cavities than an individual with harder enamel.
However, life is not only unfair, it’s also complex! Other things are very seldom equal.
SPIT AND POLISH
Saliva is one of the key players in our oral defenses. Saliva’s duties include neutralizing, diluting, and washing away the acids that erode tooth enamel. Some people have more saliva flow, others less, and this, too, has a genetic basis. More abundant saliva is an advantage in preventing tooth erosion.
Furthermore, saliva contains the minerals our teeth use to rebuild and reinforce enamel, which is under continuous attack. Your DNA controls how much of these minerals are present in your saliva. Some peoples’ genes stimulate higher concentrations of these minerals, others have less. Lower concentrations weaken this defense.
These microorganisms secrete acids that eat away at tooth enamel, eroding it and leading eventually to cavities. Researchers have identified a gene (DEFB1) which controls first-line immune defenses against these invading germs. Some people inherit a form of the DEFB1 gene for a stronger immune response, other people inherit a weaker version. Less immunity to these bacteria means more decay.
Genes shape of the developing jaw, which in turn determines the tendency for teeth to be misaligned or overcrowded. Misaligned and overcrowded teeth are more difficult for us to clean with our toothbrushes and floss. The food bits left behind encourage the formation of plaque, the growth of bacteria, decay, and cavities.
ADAPT AND THRIVE
So, your DNA determines the hardness of your tooth enamel, the flow and mineral content of your saliva, the strength of your immune response to the bacteria that cause tooth decay, and the physical arrangement of your teeth. All of these genetic factors, individually and interacting with each other, define your potentials for oral health and the challenges to it. What can you do about it?
Let’s walk back through the examples discussed earlier, this time with eyes open for opportunities. Challenges posed by genetic endowment often suggest their own solutions. There are practical and effective steps we can take to improve our outcomes within the boundaries set by our individual genetic assets and liabilities.
Your daily dental hygiene routine is the primary element in your campaign for oral health. We tend to pick up the practices and habits of our parents and other role models but these, fortunately, are not passed along by our genes. We have control over how and when we brush, floss, and visit the dentist for cleanings and checkups.
Regular professional cleanings and examinations are opportunities to review your hygiene routines with your dentist, and so lead to early detection of the kinds of genetic issues we’ve discussed here. Identification of a problem is the first step toward intervention. Since DNA testing for the known dental issues is not in the mainstream yet, we must rely for now on the dentist’s experience to identify signs and symptoms of inherited dental vulnerabilities.
LINING THEM UP
The cleaning obstacles introduced by crooked or overcrowded teeth are addressed with orthodonture. We usually think of braces as a cosmetic intervention and they surely are, but there’s a wellness aspect as well. Teeth which are properly aligned and spaced are teeth we can effectively clean on a daily basis at home. By identifying misalignment and overcrowding early, and starting orthodontic care promptly, we can minimize the genetic disadvantage and maximize the payoff from our daily investment in oral hygiene.
WETTING THE WHISTLE
Hereditary dry mouth, or low saliva flow, can be addressed by things as simple as chewing (sugarless!) gum. Research has shown that lifestyle modification can also help. For example, researchers have found a connection between dehydration and erosive tooth wear. Some widely-used medications are known to reduce saliva flow. People with the hereditary tendency to dry mouth can take extra care to stay hydrated. Saliva substitutes are another potential solution. About 20% of the American population has some form of dry mouth, and this approach is seeing increased attention from researchers and product developers.
Once any genetic issues are addressed or ruled out, most of us should adopt the same fundamental strategy of learning and adopting the well-established practices of oral hygiene. Details like toothbrush type, brushing technique, cleaning aids, choice of toothpaste, and flossing are things your dentist is qualified and happy to offer expert advice on.
ONE MORE OPTION
This brings us back to our first example of a common genetic issue in oral health: soft enamel. Sealants are an option you can discuss with your dentist if it seems you’re doing everything right but still seeing decay. Commonly thought of as a pediatric solution, adults in increasing numbers are finding the cost-effectiveness of dental sealants attractive.
For oral health as for general health, our parents lay out the playing field when they combine their genetic material and pass it along to us. Each of us is bequeathed a set of comparative advantages and comparative disadvantages. Though we sometimes tend to think of our genetic endowment in terms of fairness or unfairness, the reality is that it has nothing to do with justice. In terms of oral health, we have considerable control over our fates, and it’s our responsibility to use this control to get the best outcomes we can.