Causes of Dental Disease

Dental Decay

Tooth decay is caused by bacteria. The bacteria streptococcus mutans is the primary agent responsible for caries (cavity) formation. The bacteria first colonize the tooth and multiply until they form a thick plaque on the tooth. This plaque is a sticky glue designed to hold the bacterial colony in place. The thickness of the plaque then holds metabolic acids the bacteria produce as a waste product, and this acid demineralizes, or eats away, the tooth structure.

There are three factors necessary for decay to progress. First, bacteria must attach to the teeth and produce a thick plaque to hold the acid in proximity to the tooth. Second, a source of food for the bacteria must be available. Third, there must be time enough for the acid to be produced and held in place for the demineralization to occur. If any one of these factors is disrupted decay cannot occur.

Brushing and flossing mechanically disrupt the bacterial colony, preventing plaque formation, which in turn prevents the acid waste product production that causes the decay. Brushing and flossing also help remove the sugary residue from food that the bacteria feed on.

Avoiding sugary foods deprive the bacteria of their food source. Bacteria prefer easily fermentable simple sugars. Sugary foods that stick to the teeth provide a sustained sugar supply for the bacteria, and simple starchy foods such as crackers are easily changed to simple sugars by saliva in the mouth.

If brushing and flossing occur at regular intervals each day, there will not be enough time for the bacteria to colonize, form plaque, and produce acid. Also, if sugar exposures are kept to a minimum, the food needed for bacterial reproduction is not as readily available, which breaks the cycle.

Some people wonder how they get cavities if they take care of their teeth. The answer to this is that it is sometimes hard to clean all plaque out from all areas of the mouth, and it is sometimes hard to keep ahead of the cycle if a diet is high in the sugar that fuels the bacteria. At the dental office, we can advise how to brush and floss properly for each individual situation, showing how to give extra attention to problem areas. We can also review diet habits to help patients make practical changes in sugar intake. We can also provide fluoride treatments to remineralize teeth that have shown some decalcification from the acid waste of the bacteria.

Periodontal Disease

As described in the explanation of dental decay, bacteria are continually reproducing in your mouth, forming plaque, which is a biofilm of the bacteria. This plaque is thick and keeps oxygen from reaching many areas within your mouth, such as under the gum line. While many different types of bacteria may cause the plaque film to form initially, the dangerous periodontal bacteria (which are anaerobic, or oxygen hating) take advantage of the oxygen deprived conditions provided them by these other bacteria, and proliferate wherever there is a pocket without oxygen.

Whereas sugar is the food culprit in dental decay formation, the diet aspect that affects periodontal disease is not carbohydrate, but rotting food particles of any type. Anytime food particles remain caught in the tight spaces between teeth, they can physically block oxygen from getting into the areas and cause proliferation of anaerobic bacteria. This is in addition to contributing to plaque biofilm formation.

The bacteria plaque that forms from the above processes can become hardened when minerals in saliva come in contact with it. This hardened, calcified plaque is called calculus, and it coats the roots of the teeth where periodontal bacteria have colonized. When the tooth roots become covered with this hardened substance, the body starts to think of the tooth as a foreign object, and it reacts much the same way as it would to a splinter. Inflammation occurs, white blood cells are drawn to the area, and an increased blood supply is provided, and the result is reddened, puffy gums that bleed on pressure.

As bacteria levels increase and calculus becomes more entrenched, the infection processes of inflammation and toxin release affects collagen formation, and this causes gum tissue to loosen, moving it away from the tooth (like a turtleneck that is stretched out). This allows the bacterial toxins to attack the space between teeth and gum, causing a destruction of the bone supporting the teeth. If the bone level is reduced to the point that there is not enough bone level to hold the teeth, the teeth may be lost.

The infection process continues as the disease progresses to bone loss, and at this stage it can become serious because the bacteria can enter the bloodstream. It is believed that these bacteria may contribute to many serious illnesses as the process that occurs in the mouth spreads to other parts of the body, causing inflammation, plaque development, and blood clotting. Periodontal bacteria have been implicated as a factor in heart disease, stroke, premature birth, pneumonia, diabetes complications, some surgical complications, and increased mortality from other diseases.


There are two types of tooth erosion, mechanical and chemical. Mechanical tooth erosion, also known as abrasion, is caused by using an abrasive material in the mouth during eating, brushing, or in the environment. Chemical erosion is caused by acidic demineralization of the tooth structure by foods, beverages and environmental factors such as pool water pH.

Mechanical erosion usually occurs in specific areas that are exposed to the abrasive. Brushing too vigorously or using a particularly abrasive dentifrice such as a toothpaste designed for stain removal can cause erosion. People who work with sandblasting materials or work in dusty areas can abrade their teeth if the material gets in the mouth. Historically, people who ground grain in a mill showed accelerated wear of teeth.

Chemical erosion is common, especially in people who drink large amounts of acidic beverages. Many drinks are acidic, including sodas, juices, and sports drinks. Improper pool maintenance can also lead to chemical erosion of teeth. Anyone who spends a lot of time at a pool should check with personnel to make sure that the pool chemicals are properly maintained. Eating disorders and gastrointestinal distress are also common causes of chemical tooth erosion. Bulimia and gastro-esophageal reflux disease (GERD) both expose the oral environment to the gastric acids that can dissolve teeth. If a person is at risk for chemical erosion due to diet, environment, or health problems, it is advised to rinse the mouth with water after the exposure to dilute the acid, and to delay brushing for about an hour to avoid scouring the teeth when tooth enamel is softened and brushing can actually aggravate the erosion.

What is the solution to preventing these diseases?

The obvious prevention to disease is to brush and floss regularly, which works to mechanically break up the bacteria in the mouth. In the case of dental decay, brushing the sugar from food off the teeth robs the bacteria of their food source, so they cannot proliferate and produce the acid waste products that cause decay. As for periodontal disease, flossing get rids of food particles and plaque biofilm that cause the oxygen deprived environment that the anaerobic bacteria need. In short, scrubbing all surfaces, especially the crevices between the teeth, keep bacteria from doing their dirty work.