When i was around 10-11 yrs old I fell & chipped my front central incisor (bottom part) , over the years i had bondings done. The top portion of my tooth which is my real tooth is becoming yellow and darker compared to my other teeth and now is darker than the bonding I have on it now.i had a pulp test and I felt it , so the pulp is not dead, the tooth is sensitive sometimes. Should I be getting a root canal ? If the pulp is still alive what is causing the discoloration ? How can I fix this?