An infected root canal can cause all kinds of problems including bad breath. You can certainly have a root canal problem without ever noticing a bad taste in your mouth. But sometimes the infection can create a very foul taste and odor. Such was the case of a patient I saw recently. She came in puzzled about the source of her stubborn bad breath problem.
When this occurs you might try all kinds of mouthwashes and fresh tasting mints as my patient had. She even brushed her teeth all day long trying to get rid of the taste. But if you have a root canal infection none of these attempts will be successful. Let me explain.
If you have an infected root canal it means the dental pulp on the inside of your tooth has abscessed or "died." The pulp is the soft tissue found beneath the hard outer tooth structure known as dental enamel. This dental pulp tissue is very important when you are young since it actually forms the hard outer tooth structures.
Once the tooth completes its development the pulp has no vital function in maintaining your tooth. That's why you can still retain your tooth even if the pulp "dies."
If this abscessed dental pulp remains inside your tooth long enough it will cause an infection in the bone surrounding your tooth. All of this can happen with or without there ever being any pain and/or swelling.
In fact many people I've treated in more than twenty years as an endodontist (root canal specialist) are surprised to find out they have an abscessed tooth and it has never caused any pain at all.
Once you have this infection in the bone surrounding your tooth it will seek to work its way out to relieve the pressure that builds up with an infection.
This infection can burrow its way through the bone and cause a small hole to form in the overlying gum tissue. Pus will then drain through this small hole. Now the infection has established a path of drainage and this will keep your tooth from hurting.
The problem is you have this infection in your jaw being fed by a bad tooth. This draining pus can produce a foul odor and give you some really bad breath. Of course this isn't the only possible cause of bad breath!