Is it normal to have extra saliva after root canal therapy?

Yes. Any time that work is being done in the oral cavity there can be an increase in salivary flow. Not to worry.
Not unusual. When one has dental work done, it is not uncommon for the physical stimulation of the tissues to result in increased salivary flow.
No. You may be reacting to the temporary filling placed to cover the root canal access or a change in contour of the tooth. Most endodontist shorten the tooth after the root canal is done to keep it from hitting the opposing teeth as it heals. The tounge sometime will not leave it alone and the result can be excessive saliva. See your dentist to evaluate.

Related Questions

Why is my mouth so tender after root canal therapy?

Normal. It is normal to haved tenderness after root canal rct root canal therapy. It should resolve shortly or you need to call the dentist or go to another dentist.
Expected. There is often some discomfort for a short period of time following root canal therapy. Your dentist should be able to prescribe medications to lessen your discomfort. If the discomfort continues for more than several days, go back to your dentist for evaluation.
Pain. It is not uncommon to have pain following a root canal. I usually tell my patients to expect the tooth to be sore for 48 hours. They had injections for numbing, clamps on the gums, drilling and instrumenting of tooth, and a local inflamation at the tip of root. These all can make the tooth sore to bite on and the area to ache. It will usually inprove within the week.
Surgical procedure. Root canal therapy is actually a minor surgical procedure. Any surgical procedure is often followed by some soreness or discomfort. The periodontal ligament and other tissues that surround your root in the bone become temporarily inflamed which in turn causes the soreness.
Very common. It is normal to feel some tenderness in the area for a few days after your initial root canal appointment. These symptoms are temporary and usually respond very well to NSAIDs or Tylenol (acetaminophen) OTC. If you have severe pain or pressure that lasts more than a few days, contact your dentist.

What should I do to help my tooth heal after root canal therapy?

Soft diet. One thing you can do for a little bit is to use some ice to help healing and keep your diet soft. You don't want to be chewing things too hard or that require a lot of effort to eat. After the procedure, by keeping your diet soft, your tooth will thank you! Try this for a couple days to give your tooth the chance to rebound!
Give it time. Dental treatment often is like a bruised knee. It's sore and needs a little time to settle down. Avoid chewing on hard foods and avoid chewing gum. Use common sense to guide you through the healing. Usually most pain is gone within a few days. If pain persists beyond one week you should contact your dentist.

Why do I feel discomfort after root canal therapy if the nerve is gone?

Phantom pain. When nerves are injured there is sometime a condition where there is "memory" and if the nerve is gone, the rest of the nervous system remembers the nerve and there is the sensation of pain. This is a complex and poorly understood conditon. It happens with loss of limb as well. It also could be inflammation in the root canal itself. Discuss with your dentist or endodontist.
Periodontal Tissues. Yes the nerve in the tooth is gone, but the pain comes from the bone and gingival tissues which are still very much alive and have sensation. Biting pain is the most common and that has nothing to do with the nerve in (was in) the tooth.
Possible infection. Root canal therapy is necessitated by the death of the nerve inside the tooth. This is often caused by bacteria in the nerve...An infection. Often, this infection migrates to the opening at the tip of the root and from there into the bone outside of the root. This infection can persist for awhile after the root canal procedure is completed. It is often accompanied by pain and swelling.
Micro trauma. If the tooth area was inflamed before the treatment and the treatment was extensive or complicated, it is possible that the gum or ligament of the tooth can be inflamed and need several days to calm down. Bite adjustment may be necessary, speak to your treating dentist.

Can a person smoke after root canal therapy?

Not recommended. OK, you should never smoke under any circumstances. However, do not smoke for 12 hours before treatment and for 72 hours after root canal therapy to facilitate the healing. Quitting smoking is unbelievably difficult, but I know you have the "guts" to do it.
No Smoking. It is better not to smoke at all regardless. Take care of your health.