Thanks for sharing your concern.
What made you think that it is a cancer? Dont be worried at all.
For detecting cancer an its type biopsy
is done not an x ray
. Your dentist
must be needing a bigger x ray like OPG for that he could have asked your son to visit hospital.
In x ray you can see hard and soft tissues like teeth, bone, cyst, periodontal abscess
, periapical granuloma
, necrotic areas , bening tumours or quite rarely it may be malignancy too .
Dark shadow or areas seen in the x ray films is called radiolucent areas . Any pathology associated with the tooth can appear radiolucent .
You have not mentioned the other symptoms, like pain and mobility in the tooth. Any associated bleeding?
Exact diagnosis can be made by clinical examination and related x rays.
i suggest you to get an OPG radiograph done that shows the exact relation of the pathology with adjacent teeth , jaws and other vital structures.