Tooth root fractures---causes?

I had a root canal done 15mos ago on a molar. About a week ago, it started hurting, and my gums started to swell…by the time I got in to an endodontist, it looked like I had a tennis ball in my mouth.

He diagnosed a tooth root fracture (same root that was involved in the root canal) I have to have it extracted.

Would a poorly performed root canal cause the fracture (by weakening the root)?

I haven’t had any impacts to my face lately, so I can discount an impact causing the root to break.

What causes these things?

this happened to me on a tooth that was root canal-ed when i was 14. root canals weaken the tooth, it doesn’t get any nurishment and is dead, like hair and fingernails. they can break and crack at any time. a crown usually protects the tooth a bit.

mine broke on a potato chip loaded with onion dip. i felt a sharp stabbing pain and then within a day or 2 infection with quite a bit of swelling. draining abcesses are really fun! the break didn’t show up on xray though, i decided to have the tooth extracted and during extraction the break was revealed. they wanted to do a 2nd root canal. no way, teeth only get one chance, after that they are out of there!