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Rusty Cars and Tooth Decay

Just before heading to college, I bought a used 1970 Ford Maverick for $900. It was a dependable little car that got me from points A to B. It did have some rust and over the years, the rust spots became larger, eventually the suspension system collapsed through the rust, and I had to tow it to the junkyard. I'm sure if I had the means and know-how to treat the rust when it was small, I might still have the car today. So, what do rusty, old cars and trucks and teeth have in common?

Well, I think of tooth decay as being a great analogy to rust on a car. The decay starts out small and if left untreated in an unchanging environment, it will continue to grow and eventually, cause tooth failure. Depending on the extent of the tooth decay, the tooth may even need to be removed. So, two things must exist for there to be tooth decay. A vulnerable tooth and acid. The common ways acid gains access to the tooth is through diet and bacteria.

What makes teeth vulnerable to dental decay?

Genetic disorders. There are disorders in tooth development that leave the teeth at higher risk of fracture, wear, and decay. Dentinogenesis imperfecti, amelogenesis imperfecti, and ectodermal dysplasia are a few genetic variations that weaken teeth. Fortunately, we don't see these very often.

Tooth shape. Tooth shape can be considered a vulnerability due to deep grooves where plaque, bacteria, and acid can hide. Molars have varying degrees of groove angles and depth on the chewing surface and on their sides. The deeper the grooves, the harder they are to keep clean. When there is recession of the gums, areas between the roots can be difficcult to clean.

Tooth position. Where the teeth form in the mouth can be a vulnerability factor. Teeth can erupt anywhere in the mouth and body. Did you know teeth can actually form in other areas of the body? They are called teratomas. When teeth are crowded in the mouth, it makes it difficult for a toothbrush and floss to consistently remove acid, plaque, and tartar. Wisdom teeth that erupt sideways can put adjacent teeth at risk for decay. Even in perfectly straight teeth, the point where the teeth touch is a high frequency area for decay development.

Pregnancy. Pregnant women can be more prone to dental problems and tooth decay due to several reasons. I thought this article was relevant: Am Fam Physician. 2008 Apr 15;77(8):1139-1144.

Oral health care in pregnancy is often avoided and misunderstood by physicians, dentists, and patients. Evidence-based practice guidelines are still being developed. Research suggests that some prenatal oral conditions may have adverse consequences for the child. Periodontitis is associated with preterm birth and low birth weight, and high levels of cariogenic bacteria in mothers can lead to increased dental caries in the infant. Other oral lesions, such as gingivitis and pregnancy tumors, are benign and require only reassurance and monitoring. Every pregnant woman should be screened for oral risks, counseled on proper oral hygiene, and referred for dental treatment when necessary. Dental procedures such as diagnostic radiography, periodontal treatment, restorations, and extractions are safe and are best performed during the second trimester. Xylitol and chlorhexidine may be used as adjuvant therapy for high-risk mothers in the early postpartum period to reduce transmission of cariogenic bacteria to their infants. Appropriate dental care and prevention during pregnancy may reduce poor prenatal outcomes and decrease infant caries.

Dental work. Dental work can also create areas that are hard to consistently clean and can lead to recurrent decay . This leads to larger, more invasive procedures to treat the tooth. It's extremely important for dental providers to stress the maintenance of their crowns, fillings, and other dental work when they are placed to prevent recurrent decay. Small enamel cracks can also provide an entry point for the decay. Iatrogenic damage can cause areas for decay to enter the teeth.

Acid wreaks havoc on teeth and is the primary cause of tooth decay. Inside enamel, there is a balance of calcium and phosphate ions. The phosphate ions in saliva capture and buffer acid and helps the tooth add calcium to the enamel. When this balance is upset by stronger acid or a long term acid exposure, the minerals in the teeth are lost and tooth structure is damaged. It erodes the enamel and creates entry points for the decay and bacteria to invade the tooth.

In today's world, there are seemingly endless sources of consumable acids. Soft drinks, citrus fruits, vinegar, wine, and raw materials that can be turned into acid, such as sugar and some artificial sugars to name a few. Regular soft drinks are a double whammy because they contain acid and sugar.

Stomach acid isn't a consumable acid, but it can have a dental outcome similar to other acids. Patients who have long standing gastroesophageal reflux disease or suffer from bulimia nervosa usually show signs of enamel erosion which can lead to tooth decay. Another condition that results in a higher risk of tooth decay is xerostomia (dry mouth) because saliva contains buffers that help neutralize acid and helps inhibit bacteria that convert sugars into acid.

The human mouth harbors many strains of bacteria, viruses, and yeast that comprise the oral flora. Not all microbes are harmful, in fact, some are helpful. The bacteria that is harmful to teeth converts sugar into acid. One such bacterium is called Streptococcus mutans. It is adept at attaching itself to teeth and breaking down dietary sugar into acid. The more acid and sugar a person consumes, the more selective the environment for the acid producing, tolerant bacteria. Studies have shown once you consume sugar, the pH drops for about 15-20 minutes. Anything you can do to reduce that exposure will help prevent tooth decay. These bacteria can hide in and around tartar, so it's important to get regular dental cleanings and checkups.

So, what can we do to reduce acid exposure on the teeth? In some people, it takes a lifestyle change and lifestyle changes can be really hard. I've had patients who were addicted to soft drinks. They had rampant tooth decay and it wasn't easy for them to stop drinking soft drinks even after knowing what it was doing to their teeth. I've had some people tell me straight out, "it's not going to happen." I've recommended trying flavored water as a soft drink substitute and it helped some patients kick the soft drink habit and reduced the incidence of new decay. If cessation isn't in the cards, then soft drinks are better consumed quickly rather than sipping on them all day. In a perfect world, you would want to immediately follow the soft drink with water, thoroughly brush your teeth and tongue remembering that teeth have 5 surfaces and all must be cleaned, and it also helps to chew sugar-free gum with xylitol to stimulate saliva flow.

I believe reading ingredient labels is important to know what you're putting in your body for your overall health. Looking for sugar and acids in products and avoiding the ones that contain them will prevent you from unknowingly consuming those ingredients. If a product has sugar and acid, you can also think about the "stickiness" of the product. If you consume it, how long will the product stay on the teeth? If it's sticky and stays on the teeth, the longer it provides fuel for the oral bacteria to produce acid.

Patients who have heartburn, dental erosion, or suspect they have gastroesophageal reflux disease, or bulimia nervosa should be referred to their primary care manager for diagnosis and treatment options.

Patients who suffer with xerostomia should look into saliva substitutes, stay hydrated, maintain excellent dental hygiene, and ask about fluoride or MI paste options. Fluoride and MI paste helps strengthen the teeth and makes them more resistant to decay. In some patients, a medication can be prescribed to stimulate saliva production, but with most medications, it can have adverse side effects.

All teeth are susceptible to acid exposure by disrupting the demineralization-mineralization balance but especially certain teeth. Regular dental visits increase the chances that dental decay can be found when it's small and easily repaired before a catastrophic failure happens. Likewise, I believe had I known a good auto body mechanic while I was in college, I would still have my Ford Maverick.

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