We’ve all heard this question at some point in our careers: “Doc, why does my spouse who never flosses or brushes as much as I do have no cavities, and I floss daily, do all the right things and yet always seem to need dental work?” Likewise, why do healthy people who eat right, exercise and not smoke still get cancer? I’m pondering this question lately and wondering which factors ultimately cause disease. Genetics? Environmental influences? Or do we do it to ourselves? Of course, we could also toss in pure luck, either good or bad, for extra ambiguity.

As dentists, tooth decay is assessed with risk. That is, how high or low one’s risk of developing caries will influence treatment methods and approaches. The American Dental Association^1-3 describes tooth decay as “multifactorial” and that one’s caries risk includes dietary habits, exposure to fluoride, home care, etc. Basically, developing decay is the tipping point of the delicate balance of the mineralization of enamel to demineralization. What we do or don’t do either shields the enamel or destroys it. That all sounds simple and scientific – reduce your acid and sugar intake, brush and floss frequently, and your enamel is protected. So, if everyone adhered to those righteous rituals, as they should, then why does caries still affect 97 percent of the worldwide population? Assuming everyone visits the dentist regularly, that means either good home care and diligent diets are not genuinely followed, or another factor, such as genetics, may be at play. But if genetics dictates destiny, then, by the same logic, children of edentulous patients should also be edentulous, and children of parents who do not have any cavities should also have no or low decay. That is not the case, however, and the extent to which our genetic code influences our health is partial.

In cancer cases, for example, the delicate balance between healthy new cell growth and cell death is disrupted, causing abnormal cell growth to go into overdrive. The goal of prevention should be to minimize cell toxicity — consuming the perfect combination of antioxidants, reducing intake of all that destroys cells and exercising to help generate healthy new cells. And assuming we have no genetic predisposition to cancer, we should all be cancer-free if we followed those practices right? Sadly, this is not true.

I have many patients who meticulously do all the right things, and yet still have an increased incidence of decay. By the same token, I personally know folks who smoked well into their eighties without a scratch. What’s the answer?

I don’t know exactly, except that the interplay between personal habits, genes and susceptibility to disease are very complex. Let’s not forget luck. It must be very frustrating for patients who adopt good dental hygiene habits and yet face many dental challenges. My heart reaches out to those patients. It must be even more difficult for oncologists to explain why their healthy patients with healthy lifestyles are inflicted with deadly diseases. It is difficult and distressful to understand why some of us are armed with healthy behaviors and yet lose battles with diseases. Life seems unfair in this regard, and sometimes, after all has been exhausted, the best I can do is comfort my frustrated patients and be their guide through the process of returning to oral health.

References

1. Berg JH. “The marketplace for new caries management products: dental caries detection and caries management by risk assessment.” BMC Oral Health. 2006;6 Suppl 1:S6.”
2. Selwitz RH, Ismail AI, Pitts NB. “Dental caries.” Lancet. 2007;369(9555):51-9.
3. Featherstone JD. “Caries prevention and reversal based on the caries balance.” Pediatr Dent. 2006;28(2):128-32; discussion 92-8.