Which restorative material is known to cause stains on teeth?

The choice indicating that both amalgam and composite can cause stains on teeth is correct because each material has characteristics that can lead to staining, albeit in different ways.

Amalgam restorations, which are made from a mixture of metals including mercury, silver, and tin, can cause dark discoloration around the margin of the filling due to corrosion over time. This happens as the restorative material interacts with dietary factors and oral bacteria, leading to a darkening effect on the surrounding tooth structure.

Composite materials, although generally more aesthetic and tooth-colored, can also be susceptible to staining. This is particularly true for lower-quality composites or those that are not properly polished, making them more vulnerable to absorbing pigments from foods and beverages, such as coffee, tea, and red wine, which can lead to discoloration.

Considering these properties, both amalgam and composite materials are capable of causing stains on natural teeth, making them both relevant in discussions regarding aesthetic outcomes in restorative dentistry.