My dentist wants to do a repeat root canal on an upper first molar, and I want to know if it’s necessary. The temporary filling fell out a couple of weeks after my dentist completed the root canal. My dentist says I now have an abscess in the gum around the tooth, so she wants to repeat the root canal. However, the tooth doesn’t hurt at all. Is this necessary treatment, or are antibiotics enough? – Thanks. Japheth from WY
Japheth,
During a root canal, your dentist removes the infection inside the tooth and seals the root with a filling material and cement. That seal must stay protected, or bacteria can re-enter the tooth and restart the infection. A temporary filling protects the tooth until you get a crown or a permanent filling.

Temporary fillings are intentionally easy to remove because they will be replaced with a final restoration. If a temporary filling falls out, saliva can seep into the tooth within days, breaking down the root canal seal. Once that happens, the infection can return, although it may be painless.
Will Antibiotics Be Enough to Treat a Tooth Abscess?
Antibiotics cannot reach the source of the infection inside the tooth.
Here’s why they cannot heal an abscess:
- Antibiotics travel through the bloodstream, but there is no blood supply inside a tooth.
- They may temporarily reduce swelling or an abscess in the surrounding bone or gum.
- Once you stop taking them, the infection typically returns.
Repeated antibiotic use also increases the risk of antibiotic-resistant bacteria, which creates unnecessary health risks.
Why It’s Risky to Delay a Repeat Root Canal
Even if the tooth doesn’t hurt, an untreated infection can spread. Infections in the jawbone—especially in the upper jaw—can extend to nearby structures, including the sinus, eye, or brain. In addition, bacteria left inside the tooth allow decay to progress from the inside out, eventually making the tooth impossible to restore.
Baton Rouge family dentist Dr. Ryan Perry sponsors this post. Please read about how he strives to provide his patients with the best care possible.