last year i had all my teeth checked and some treated i thought...then just about a month ago a tooth got extremely sensitive and i was advised to have it treated - root canal. i heard its really painful but in my case it did not hurt a lot in fact i was able to go to work and did not have to take the painkillers. so it's case to case and finally just last Wednesday, 13th it had permanent filling and light cure whatsoever.I will not have another root canal though : )