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Dentistry/Root Canal Troubles


I went to the dentist originally complaining that my last molar on the top left side was bothering me. My dentist said he had previously filled that cavity 2 years ago and it looked fine. He then turned his attention to a cavity I didn't know I had on the my last molar on the bottom left. He filled it and sent me on my way. After a week or so I started experiencing hot and cold sensitivity (especially cold) and it lingered. He told me I that I needed a root canal. I had that root canal 2 weeks ago from today and something is still bothering me on that side. I feel pressure when I bite down. First I thought it was my bite so he messed around with that a bit and put me on an antibiotic for a red swishy bump on my gum behind the last tooth where he did the root canal. It used to be very tender but after I finished the antibiotic it doesn't hurt anymore but it hasn't disappeared. When I touch my tongue to the tooth that he worked on I get this tin foil taste. ( sorry I don't know what other way to explain it ) after telling my dentist that he said that the tooth could be fractured and it might need to be extracted. I'm only 20 years old and I don't want to lose my teeth yet haha. I guess my question is how could he tell if my tooth is actually fractured? He took new x rays and he said they look normal to him. Should I get a second opinion and see a endodontist? If I'm experiencing hot and cold sensitivity still it can't possibly be the tooth he worked on because the nerve as been removed, does that mean he did a root canal on the wrong tooth? Why does it hurt to bite down? Any advice you can provide for me is greatly appreciated.

A troubled patient,

ANSWER: Hi Amanda,

I'm sorry all this is going on. It gets to be frustrating for you when the dentist starts talking about extractions when you had just a "simple" filling done. It's hard for me to diagnosis your problem since I can't exam you or see your X-rays, but let me try to at least help you understand what might be going on.

Let's deal with the possible fracture first. Biting sensitivity is one possible symptom of a fracture, but I would NEVER make that diagnosis on biting only. In our office, we use a hard plastic instrument that fits on each cusp of the tooth, one cusp at a time.The we have the patient bite down firmly and release quickly. If you have pain when you release, not when you bite down, then a fracture is likely. You can try this yourself using a pencil erasure. Just put the erasure on each cusp #bump# of the tooth and bite down firmly and release quickly. X-rays are no help in detecting fractures because fractures don't go in straight lines and X-rays do, so tooth structure is always superimposed on the Xray image so you can't see a fracture unless it is really big, which they rarely are.

Another reason the tooth may be biting sensitive is that the root canal is not working and there is infection at the end of the root. That's why your dentist put you on antibiotics and might explain the red bump on your gums. Unfortunately, I would need to exam you to tell you where and why it hurts to bite down.

You are absolutely correct about your hot & cold sensitivity. Once a root canal is done, that tooth can't feel temperature and it's coming from another tooth.

At this point, with what you have already gone through, I think a 2nd opinion from an endodontist would be a good idea. He/she would be able to evaluate your sore biting, continued temperature sensitivity, and evaluate the root canal that has already been done and give you the info you are looking for to move forward and out of pain.

I hope this helps. Please let me know what you find out. Complicated situations like this are always interesting to me. Good Luck!

Gary Backlund DMD, MSD

PS- You're an excellent historian of your situation and sound like a very smart young woman :-)

---------- FOLLOW-UP ----------

QUESTION: Thank you! I'll be making an appointment with an endodontist on Monday morning but till then I have one more question cause I think I might be on to something (: It hurts when I bite down AND when I release. I had a cavity filled on the tooth next to my root canaled tooth. The filling is right on the side of the tooth, basically in between the two. It hurts to floss inbetween there, I feel like I'm almost pulling something out. Would a loose filling cause hot and cold sensitivity and painful biting? Can a filling be loose without it necessarily having to "wiggle". How can you tell if it is loose in the first place?

I appreciate you taking the time to answer my questions. You've already helped me better understand my situation!

Hi again Amanda,

Having a loose filling could certainly cause all your symptoms, especially the hot and cold sensitivity. You really can't tell if a filling is loose by yourself, but it wouldn't really have to be loose to give you those sensations. There could be decay around or under the filling and the filling would still be firm in the tooth. The fact that it hurts to floss might mean the decay in under the filling between your teeth and it could feel like it's coming from the root canal tooth next to it. You might indeed be on to something. Make sure to tell the endodontist your suspicion when you go in for an examination. The good news is, if that's the situation, it will certainly be less money than another root canal or an extraction and an implant or bridge.

Like I said before, please let me know what you find out.

Gary Backlund DMD, MSD


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Gary Backlund, DMD, MSD


I am an Endodontist ( root canal specialist ) and can answer questions about root canals and their treatment. I cannot diagnose or treat online, but can answer general questions. I have been a specialist for 25 years and am Past President of the Washington State Association of Endodontists.


25 years practicing as a specialist

American Association of Endodonists, Past President Washington State Association of Endodontists.

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