During most periodontal procedures, including periodontal cleanings, the tooth is cleansed under the gum's edge. This usually causes minor gum bleeding, which is often unnoticed by the patient. However, when bleeding occurs it is likely that some mouth bacteria will enter the bloodstream (bacteremia). This is a common phenomenon, and may even occur with toothbrushing if the gums are inflamed. Normally the bacteria are destroyed when they enter the bloodstream, but with certain medical conditions they may potentially cause a problem. If the bloodflow is slowed as it passes through the heart, such as may be seen with mitral valve prolapse, the bacteria may have time to adhere to the vessel walls, forming a colony that causes an infection. This may lead to bacterial endocarditis, a serious medical condition. Thus patients with mitral valve prolapse or other heart conditions need to take antibiotics to ensure the bacteria are destroyed. Similarly, a newly placed orthopedic joint may be susceptible to infection, and antibiotic coverage is recommended for two years after joint placement.
For almost all cases, taking a single dose of antibiotics one hour before your appointment is all that is needed, unless surgery has been scheduled. Here the antibiotics may be continued for 7 - 10 days. Below is a listing of the current American Heart Association's Guidelines.
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