I got a root canal and a dental crown 8 months ago and today, when i was biting down on a piece of bread, i felt a severe and shocking pain in the area where i have the crown. what does the symptom indicate?

Does it still hurt?: If the pain only occurred that one time it was probably from something being jammed between the gum and tooth. A Root canal removes the nerve from the tooth so pressure , hot, or cold usually doesn't hurt. If there is continued pain with pressure on the tooth then there is probably still infection around the tooth's roots. An x-ray would help to determine this.

Tooth Pain: Your pain may be a one time occurence, just by biting too hard on that tooth at that instant. Should it happen again, please see your dentist to have the tooth re-evaluated.

One time or more?: If this is a one time occurrence it may be of no significance. If the problem repeats it may be residual infection or a fractured root. If problem recurs, see a specialist Endodontist.