What health issues can an infected tooth cause?

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In infected tooth can cause medical problems throughout the body, and I had this happen to me many years ago. It was infected below a crown and even my dentist missed it. I got sicker and sicker with a very bad bronchial cough and fatigue, and more and more expensive antibiotics didn't help. After 10 months, I couldn't climb stairs. There was a periodontist at the end of my street. He cut a flap in the gum and showed me a long vertical crack below the crown, took out that tooth, and 2 days later, I was completely OK.

Infections can spread to other parts of the body, causing serious illness.

Worst case? Death. Has happened before and made the news.