I’m anxious about dental procedures and want to make sure I’m not doing more treatment than I truly need. I had a root canal on my upper right canine, but the temporary filling came out, and I later noticed an abscess on my gum. I went back to my dentist, and he said I need a second root canal to fix it. The abscess doesn’t really hurt unless I press on it, so I’m trying to understand how serious this is. Is the abscess dangerous if it isn’t painful? Could antibiotics treat it, or is another root canal the only realistic option? Thanks. Leighanne

Leighanne,

A successful root canal depends on maintaining a tight seal after the infection is removed. Once your dentist cleans and fills the root, they place a temporary filling to protect it from saliva and bacteria. That protection is meant to last only until the final restoration, which is usually a crown.

When the temporary filling comes out, saliva quickly compromises the seal. Over several days, bacteria can re-enter the tooth and undo the benefits of the root canal, even if you don’t notice symptoms at first.

Why Can’t Antibiotics Fix an Exposed Root Canal?

It’s reasonable to hope that antibiotics might prevent re-treatment, especially when there’s no pain. Unfortunately, antibiotics can’t reach the infection inside the tooth.

Here’s what antibiotics can—and cannot—do in this situation:

• They may calm an abscess in the surrounding bone or gum.
• They cannot disinfect the inside of the tooth.
• Stopping antibiotics usually allows the infection to return.

Using antibiotics without addressing the source also increases the risk of antibiotic resistance.

What’s the Risk of Doing Nothing?

Leaving the tooth untreated isn’t a safe option. Jawbone infections can spread beyond the mouth, particularly in the upper jaw. Over time, bacteria inside the tooth can also cause internal decay, weaken the structure, and make saving the tooth impossible.

Brian LeSage, DDS, an accredited fellow of cosmetic dentistry in Beverly Hills, sponsors this post.