Final answer:
An overhang occurs when there is excess restorative material extending beyond the cavity margin due to improper wedge placement, leading to potential dental issues.
Step-by-step explanation:
Excess restorative material that extends beyond the cavity margin because of improper wedge placement is referred to as overhang. This issue occurs during dental restorative procedures when the material used to fill a cavity is not properly contoured or adapted to the cavity preparation. An overhang can lead to plaque accumulation, which can cause periodontal disease or secondary caries. Proper technique and placement of the restorative material, along with the correct use of a matrix system and wedges, are critical to prevent such issues.