Final answer:
The radiopacity located mesial to the root of the lower right first molar refers to the presence of a radiopaque structure or material adjacent to the root. This can be seen in x-ray images and is often caused by dental fillings, crowns, or other dental prostheses.
Step-by-step explanation:
The radiopacity located mesial to the root of the lower right first molar is the presence of a radiopaque structure or material in the area adjacent to the root. This can be seen in an x-ray image of the tooth, where the radiopaque material appears as a dense or white area.
One example of a radiopaque structure in this location could be a dental filling. When a tooth is filled, a radiopaque material such as an amalgam or composite resin is used to restore the tooth's shape and function. This filling material would appear as a radiopaque area adjacent to the root of the lower right first molar in an x-ray image.
In addition to fillings, other radiopaque structures that may be located mesial to the root of the lower right first molar could include dental crowns, dental implants, or other dental prostheses.