National Dental Assisting Examining Board (NDAEB) Practice Exam

What kind of environmental factors can cause exogenous stains?

1. Medications

2. Fluoride treatment

3. Food and beverages

4. Reducing sugars

The correct answer is: Food and beverages

Exogenous stains are those that originate from external sources and can adhere to the tooth surface, causing discoloration. Food and beverages are primary contributors to these types of stains, as certain items possess pigments or tannins that can leave residue on teeth. For instance, substances such as coffee, tea, red wine, and dark sodas are well-known for their staining capabilities due to their inherent color properties. These stains often accumulate over time and can be more challenging to remove without professional dental cleaning. In contrast, medications, fluoride treatments, and reducing sugars are not considered environmental factors in the same way. While medications can lead to intrinsic stains internally by affecting the tooth structure, fluoride is utilized to prevent decay and strengthen enamel rather than cause external staining. Reducing sugars, while they can contribute to the overall health of the oral cavity, do not directly cause visible external stains on teeth. Therefore, food and beverages represent the most significant environmental factors responsible for exogenous stains.