Jim,

I'm sorry if I misunderstood your post about having a another problem tooth. I did not realize you were speaking of the same tooth as it did not come across that way. My bad :/

Thanks for posting the new xray.
Yes, there is clearly an infection covering about 1/3rd of the root of this canine. From the angle that this xray was taken, it is possible that 3/4th's of large canal is calcified. This would mean that there is no access to the majority of the large canal if you were to do a root canal. Canals calcify for different reasons. Sometimes people have odd anomalies with their teeth and calcification is one of them. Other times the canal calcifies from trauma or chronic irritation from clenching or grinding the teeth.

To rule out calcification of the canal, you would need another xray taken at a different angle, perhaps a bisecting angle, as dental xrays are only 2 dimensional.

Bryanna