Please tell me, could a dental xray show an abscess?

Possibly yes: A dental x-ray can show the byproduct of bone destruction. When there is an abscess in the bone, the it appears in the x-ray by the pattern of bone destruction. However, the bone destruction can come from any number of other problems. Additionally, if an abscess is small, or limited to soft tissue, then it will not be evident on an x-ray.

Qualified yes: An x-ray is a 2 dimensional representation of a 3 dimensional object. A newly invasive abscess will not evidence bone changes for a while. Dentists have other means of determining the extent of damage and infection spread in addition to x-rays. If you suspect a problem, see your dentist asap for diagnosis and rx.

With 3D X-ray ..Yes!: A nerve related endodontic dental abscess is seen by traditional 2 dimensional x-rays performed by virtually all dentists. However, the lesion must destroy enough of the tooth's supporting bone to be seen. Often when it breaks through the socket's outer wall. The use of a 3d cone beam cbct scan, can "slice" through any intact x-ray obstructing walls to find lesions missed by 2d radiographs.