Black area on dental x ray - panicking

[Daisypod]

I had a check up this morning and one of my teeth needs so major work, it is mostly filing and she is worried about the side of the tooth breaking off so she suggested having a filing made which good over the whole tooth. In order to do thus she x rayed the area to make sure there was no problems under the filing but of course there was :( some more decay so she said we need to drill out the old filing and see what we can do from there.
This isn't great as I have a real phobia of dental treatment but always manage to get through it.
The main reason I am panicking its that under the tooths root in the jaw was a big black patch which is said she was concerned about and that she wanted a colleague to look at to discuss whether they should refer me. This was all she said.
I have no pain in that area, bottom back molar. I have no idea what it could be and she gave no indication so I am now thinking of all sorts of things. Has anyone had any experience of this who could set my mind at rest?
My next appointment is in two weeks.

I wouldn't be able to wait. I'd go back or phone and ask them to give you an appt much sooner, or perhaps to refer you urgently to the other dentist.

I had a similar thing and was told it was large sinuses. The xray was sent for the max facial docs to look at so hopefully something simple like that.

Ah just noticed it was bottom, mine was top. Definitely get seen sooner.

I rang the dentist back yesterday evening and they said they want to refer me for an opg x ray (?) Nhs the wait is 18 weeks but they could refer me privately and that would cost £45 and I am lucky enough to be able to afford that so I am waiting to hear about that. She said it was nothing sinister but they wanted to have a look at what might be going on and until they know they want me to delay the treatment.
Even though she said it was nothing sinister I am still worrying :(

Stop worrying - she has said it is nothing sinister. It is likely to be from some old infection which has left a sinus. Very common in lots of bits of the body.