I have root canal treatment done 5 years ago to my upper front teeth and since then i had my gum swollen around that teeth . what is the reason?

An x ray: You need an xray to see if there is a residial infection on the tooth that had the root canal. You also could have periodontal disease. See your dentist for the answer specific to your problem.

A few possibilities.: The swollen gum can be because the root canal failed and you got re-infected. If the tooth was crowned, it could be due to an ill-fitting crown or poorly shaped filling that is at the gum line. It could have nothing to do with the root canal and is actually caused by heavy plaque and tartar under the gum. See a dentist for proper diagnosis and treatment.

Continued infection?: Root canals are not 100% effective...They are 93-97% effective. That means there is a 3-7% failure rate. Also, if a 'post' was placed in a tooth after a root canal, this sometimes results in root fracture. And, root fracture can be a primary cause of a dental infection that requires a root canal. If a root is fractured, a root canal might not be successful in saving the tooth.

Swelling: Root canals can fail and become re-infected causing the gum to swell. It may also be that a different tooth nearby that has not had a root canal is also infected and needs treatment. Other possibilities are periodontal infection, or a poorly fitting crown or filling causing irritation. Bottom line is that your dentist needs to take a look to properly diagnose the problem and help you treat it.