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Tooth Decay — The World's Oldest & Most Widespread Disease

A Look at the Process of Dental Caries — And How to Prevent It

By Dr. Douglas A. Young


Here's how it works — specific bacteria (mutans streptococci and lactobacilli) attach themselves to dental plaque, the whitish sticky film that collects on teeth in the absence of effective oral hygiene. When sugars or carbohydrates are eaten, these particular bacteria have the ability to break down the sugars to use for their own metabolism. In the process, though, they produce acid as a by-product which in turn drops the saliva pH. At about pH 5.5 the minerals in the enamel just below the surface begin to dissolve in a process known as “de-mineralization,” in which more calcium and phosphate leave the tooth surface than enter it. The effects of early de-mineralization in enamel can be seen as a white spot on the tooth.

Dentin and root surfaces have much less mineral than enamel and are much more vulnerable to acid dissolution de-mineralizing at a much higher pH (about 6.0 to 6.5).

Bacterial acid attacks of short duration can be “buffered” (neutralized) in about thirty minutes by adequate amounts of healthy saliva, thereby returning calcium and phosphate into the tooth sub-surface. Saliva contains a lot of calcium and phosphate “ions” (charged moving particles) that continually leave the surface enamel and are replaced from the saliva, and vice versa. This process is chemically the reverse of de-mineralization and is known as “re-mineralization.” Although the white spot may not disappear, re-mineralization is nature's way of repairing early damage and returning the tooth surface back to status quo.

Nothing in nature is static, but instead it is dynamic and therefore changing constantly to maintain a status quo. Primarily composed of mineral, teeth continually swing between “DE-mineralization” from the bacteria on the tooth surface, and “RE-mineralization” from the effects of saliva. This interchange occurs on the microscopic level, but still very important in maintaining the normal balance.

The Caries Balance

Given similar habits, you might wonder why some people get cavities and others don't. This dilemma can be better understood by picturing a balance between pathogenic (disease-causing) and protective (health promoting) factors. Each individual has his/her own unique balance that dynamically changes as time goes on. The trick is to identify what is out of balance and how to tip it towards health and protection.

Pathogenic factors include the large amounts of specific acid-producing Bad bacteria, the Absence of healthy salivary function, and poor Dietary habits. By contrast, protective factors include healthy Salivary function and Sealants (to seal the areas most likely to decay), the use of Antibacterial agents, topical Fluoride, and a healthy and Effective diet.

How to Assess Your Risk

Not everybody has the same level of risk for developing dental caries; this is further complicated by the fact that the risk is dynamic and changes daily, as well as over time. Therefore, assessing the degree of risk is crucial. And let's not forget that prevention includes determining both pathogenic and protective factors — both sides of the balance.

Modern dentistry is moving toward an approach to tooth decay management that is “evidence-based” from years of systematic, accumulated and valid scientific research. In other words, it allows individualized treatment based on current science that is customized to the patient's actual risk that he/she presents with, rather than a “one size fits all approach.”

Risk assessment allows preventive and treatment decisions to manage those in greatest jeopardy. This approach allows for “targeted” management appropriate for individuals whether in low, medium, high or extreme risk groups. Protocols have been recently established based on the Age One Visit (for infants and toddlers) as well as for children age 6 through adulthood.

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