After a recent whole mouth x-ray, there were cavities beneath all my three year old veneers. Why?

Any tooth with veneers can get cavities due to lack of oral hygiene and preventative visits. We need xrays and photos to help you further. Please send xrays and photos.

Without seeing you or the xrays, I can only guess.  Sometimes patients feel that the veneers protect the teeth enough that brushing and flossing is no longer needed, however, this is not true.  Whether the dentistry was fillings, crowns, or veneers, brushing is still needed.If decay is present, replacement will be needed.

Hi:
Unfortunately without photo and X-ray it is difficult to give you accurate advice.  Please post photo and X-ray of the affected area.
Best,
Dr. Maddahi