Do you know what car oil and toothbrushes have in common? Both are designed to clean away dirt and contaminants, should be replaced every three months or sooner, and both become ineffective when deterioration sets in. You know when it's time to change your car oil, but do you know when it's time to replace your toothbrush?

Look at the toothbrush. Are the bristles bent or frayed? When was it last replaced? The American Dental Association (ADA) says that toothbrushes should be replaced every 3-4 months, or sooner. When bristles become worn-out, they lose their effectiveness.

In a study published in the Journal of Clinical Dentistry, people were given new and artificially used toothbrushes (these brushes were worn down by a machine to simulate three months of use). The new toothbrushes removed significantly more plaque and gingivitis - the earliest stage of gum disease, than the worn brushes.

In addition to the wear and tear your toothbrush goes through everyday; overtime it also can become contaminated with bacteria, blood, saliva and toothpaste. Although the Centers for Disease Control and Prevention (CDC) is unaware of any adverse health effects directly related to toothbrush use, a recommendation is to rinse the toothbrush thoroughly with water following brushing and to tap off excess water. You may also want to consider the following to protect your toothbrush from bacteria.

Do:

Wash your hands before and after brushing.
Allow the brush to air dry after each use. The bacteria most harmful will die when exposed to oxygen.
Store the toothbrush in an upright position, so water drains from it and it dries faster.
Replace it every 3-4 months or sooner if the bristles appear worn or you've had a cold or flu to prevent possible re-infection.
Clean the cover or container often to kill potentially harmful bacteria that could cause periodontal diseases, a serious bacterial infection that destroys the attachment fibers and supporting bone that holds teeth in the mouth.

Do not:

Share your toothbrush. According to the CDC, the exchange of body fluids from sharing toothbrushes could increase the risk for infections.
Re-use or share the same disinfecting solutions or mouthwashes to disinfect your toothbrushes. This may lead to cross-contamination.
Routinely cover toothbrushes or store in closed containers. This creates a humid environment that is more susceptible to bacterial growth.
Use a community toothbrush holder. If you must, clean it often, and make sure the bristles do not touch one another.
Touch the toothpaste tube to your toothbrush.

"Brush-Up" on Brushing Your Teeth and Gums

Now that you're committed to maintaining your hygiene equipment, you'll want to "brush up" on your technique.

Selecting a toothbrush: Look for a toothbrush that has the ADA Seal of Acceptance and have soft-bristles. The size and shape of the brush should be as small and as narrow as possible in order to clean the teeth more specifically and effectively.

Step-by-Step: To clean the outside surfaces of your teeth, position the brush at a 45-degree angle where your gums and teeth meet. Gently move the brush in a circular motion several times using short, gentle strokes. Apply light pressure to get the bristles between the teeth and underneath the gumline. This should not cause discomfort. Use the same method on the inside of the teeth. Move the brush in short, gentle but firm strokes, keeping it angled against the gumline.

To clean the inside surfaces of the upper and lower front teeth, hold the brush vertically. Make several gentle back-and-forth strokes over each tooth and its surrounding gum tissue.

To clean the biting surfaces of your teeth, use short gentle strokes. Since the toothbrush can clean only one or two teeth at a time, change the position of the brush as often as necessary to reach and clean all tooth surfaces. If you have any questions, ask your periodontist or dental care provider.

Don't skip the professional visits. Professional cleanings at least twice a year are necessary to remove calculus from places your toothbrush and floss may have missed. And, a professional evaluation can determine if you have periodontal diseases.

AAP Patient Page, July-September 2004, Vol. 5, No. 3;