Need help on making sense of some x-rays

[Sarar]

Hi,

These x-rays are actually for a relative of mine. She's 57 years old and a non smoker/drinker.
She's already showed her x-rays to three dentists and they all agree that the upper right central incisor and the upper left canine need a root canal. She's already booked her appointment and I'm not questioning the diagnosis or the treatment plan. I just like to know more about how to read dental x-rays and that's why I'm making this post.
I know the canine is broken and there's obviously the huge cavity that's quite near the pulp in the x-ray. Regarding the incisor, I can see the huge cavity but in both cases I can't figure out why they're in need of a root canal treatment.
I'm trying to learn what signs indicate the need for that treatment course, so any help is deeply appreciated.
Here are the x-rays:

Thank you

 

[Dr M]

Does she have any symptoms on these teeth? If the symptoms are not spontaneous and lingering and the tooth responds to vitality tests( heat and cold) , then you can get away with a normal filling only. A cavity close to the pulp only, is not in itself an indication of a root canal treatment.

 

[alakuni]

Exploring dental X-beams can be sincerely overpowering, however you're making a proactive stride towards figuring out your oral wellbeing, and that is excellent.

Assuming you're having a befuddled or restless outlook on the X-beams, make it a point to out to your dental specialist or oral wellbeing proficient. They can walk you through the pictures, make sense of what they uncover about your dental condition, and address any worries you might have.

Keep in mind, you're in good company in this excursion. Your dental group is there to give the direction and backing you want to get a handle on the X-beams and make proper moves for your oral wellbeing. Your prosperity and genuine serenity are their main concerns, so trust in their ability to help you through this cycle.