What wears down tooth enamel, and how can you prevent it?

According to the American Dental Association (ADA), bacteria start attacking teeth within 20 minutes of eating or drinking, and the assault begins with the tooth enamel. Bacteria form as food is broken down, and foods with sugar and starch are especially efficient at forming strong and stubborn corrosives.

Starchy and sugary drinks and foods form a sticky bond with teeth, keeping the acids on the tooth surface longer. Eating throughout the day, especially when combining acidic drinks and sweet or starch-based foods, adds layer after layer of plaque and bacteria that interact to attack enamel, leading to decay. Soft drinks and candy are some of the more obvious foes, but others are less well-known.

Lemons are extremely acidic and can do some serious damage to tooth enamel. Studies have shown that people who suck on lemons or use powdered citrus sweeteners have considerable wear to their tooth enamel. While drinking a full glass of water with a lemon slice or with lemon juice likely won't cause extensive damage to enamel, doing so regularly without rinsing or brushing off the citric acid can eat at enamel over time [source: TIME]. Other fruits and fruit juices can have a similar effect but are not as highly acidic as lemons.

Other sour foods also take a toll on teeth, including sour candy, which is more damaging than the purely sweet, sugary candy. Even sports and energy-boosting drinks are very high in acids and sugars -- another double-whammy that can demineralize the teeth, breaking through the enamel into the dentin and causing cavities [source: Madrigal]. Teeth also need healthy foods coming into the body to help fight the bad bacteria, so diet can play a role as well.

Brushing and rinsing after eating and/or drinking is highly effective at getting the plaque and acids off of the teeth, but overdoing it is another story. When too much pressure is exerted while brushing, not only does the force cause gum tissue damage and wear and tear on the teeth, but it also leaves the mouth dirty. Bristles don't spread out and reach particles on the teeth when a toothbrush is pressed against them too hard. Using gentle pressure and a soft versus a hard-bristled brush prevents gum issues and sloughs away the acids and bacteria lying in wait on the enamel surface [source: ADA].

Cutting back on some of these foods, drinks and brushing habits prevents a lot of enamel wear, so all of the above are controllable, but sometimes it's more than just what we put into our mouths. Damage to the outer teeth can come from the inside out, too. How? We'll take a look inside, next.

If you have ever been sick or eaten foods that just "don't agree with you," it's likely that your sense of taste registered a difference. Often a person's body is balanced by chemical reactions and acids, proteins, fats, and a whole host of nutrients and chemicals coming in and going out. When the balance is off or foods aren't breaking down properly, conditions such as acid reflux cause some regurgitation of acids and enzymes that can hurt tooth enamel.

In severe cases, those with eating disorders such as bulimia and anorexia force food from the inside out by vomiting, and the stomach acids repeatedly come in contact with teeth. Alcoholics and binge drinkers can have the same wear on their teeth as the body rids itself of too much alcohol. Not only do teeth become thin and almost transparent in these extremes, but the body also loses needed vitamins and minerals, depriving teeth of some needed nutrients, too.

Other physical conditions such as celiac disease, cancer and even pregnancy show their presence on teeth, and individuals are advised to combine medical care with regular preventative dental care and maintenance. Teeth grinding is a much more common problem that often involves an imbalance on the inside of the jaw or temporomandibular joint (TMJ). This grinding can significantly break down enamel and even lead to cracked and broken teeth. All of the conditions mentioned would likely benefit from medical and/or psychological care, but in some cases medications that help the body also can hurt tooth enamel.

Many medications, both over-the-counter and prescribed, cause dry mouth. Saliva, though a component in forming bacteria in connection with food and drinks, is also necessary for keeping the mouth clean. Keeping a wash of saliva around the teeth keeps decay from forming as rapidly and provides needed moisture for gum tissue. Blood pressure pills, decongestants, painkillers, muscle relaxants, antihistamines, antidepressants and others suck the saliva out of your mouth. Syrupy medicines also harm teeth by coating them with sticky sugar. Rinsing after taking cough, cold or allergy syrups, or having children rinse after taking them, will help keep residue from building up and attacking enamel [source: ADA].

Sometimes what happens to the teeth can be an indicator of physical or psychological problems. Keeping the mouth clean, moist and clear of acids as soon as possible will help prevent enamel breakdown. Using fluoride tooth products and fluorinated water also is proven to strengthen the enamel itself. Topical and ingested fluoride treatments are especially effective when used early on children's teeth [source: ADA]. Scientists continue to work on remineralizing the crystals in enamel and on growing actual tooth enamel proteins, but in the meantime, we can probably avoid some caustic dietary choices and be gentler with our nature-made crowns.