Cracked teeth from bad dentist work?

2 Years ago my dentist did some serious work on my back molars, and then ground the back teeth so low that they no longer touched. Now, in the last 2 months, I've cracked 2 of my back teeth so bad the fillings fell out. I take care of my teeth, and eat a good diet. This has never happened to me before - I'm wondering if bad dental work could be the cause of my newly cracked teeth?
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What do you mean by 'serious' work was done on your teeth? Are you referring to root canals? If so, you should have had the teeth crowned (capped), since root canal treatment can leave teeth brittle.... Were you seen by a dentist in the two years since you had that work done? Especially if you had 'serious' work done, six month check up visits are essential to maintain good oral health and hygiene..... I don't think it's the dentist's fault.......
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