Hi, my bottom right tooth had an old cavity. My dentist said that it looked like it needed to be refilled. So she put an onlay on it. I never had problems prior to this but now everytime i bite it hurts. i went one more time to the dentist to adjust my bite and she said she did. but it still hurts so she suggested i go again to do the same thing and if it doesn't work it means i need a root canal. Is is the dentist fault that i would need a root canal, i didn't have any pain at all before now i can't even chew on that side. please help.