* Construction/Civil Engineering: This refers to the processes of adding fill material (such as soil, gravel, or rock) to raise the level of a site and then grading it to achieve a desired slope and elevation. This is essential for building foundations, creating level surfaces for roads, and other land development projects. The "filling" is the act of adding the material, and the "grading" is the shaping and leveling of the material.
* Dentistry: In dentistry, "filling" refers to the procedure of repairing cavities in teeth. "Grading" in this context isn't a standard term, but it might refer to the assessment of the severity of the cavity or the quality of the filling material.
Without more context, it's impossible to say definitively which meaning is intended. To get a precise answer, please provide more information about the situation where you encountered this phrase.