What colour is the typical appearance of materia alba?

The typical appearance of materia alba is characterized by a white to yellow color. Materia alba is a soft accumulation of bacteria, food debris, and dead cells that can form on the teeth and gums. This substance is often more visible than plaque due to its bulkier nature and can vary in color based on the type of food consumed and oral hygiene practices, but it predominantly presents in a shade that ranges from white to yellow.

This choice is supported by the understanding that a healthy oral environment can lead to the formation of this soft debris, which is not discolored by factors like staining or mineral buildup, which would contribute to other color options in the list. The other color choices do not accurately represent the typical appearance of materia alba, as none aligns with the most commonly observed shades seen in the mouth.