Dental Admissions Test (DAT) Practice Test

What is the primary cause of halitosis, or bad breath?

1. Dry mouth

2. Eating certain foods

3. Buildup of bacteria

4. Smoking

The correct answer is: Buildup of bacteria

Halitosis, commonly known as bad breath, is primarily caused by the buildup of bacteria in the mouth. Bacteria thrive in the mouth, particularly on the tongue and in areas where food particles can accumulate. These bacteria break down food and cellular debris, producing volatile sulfur compounds (VSCs) as byproducts, which are primarily responsible for the unpleasant odor associated with halitosis. While dry mouth can exacerbate bad breath by reducing saliva's ability to wash away food particles and bacteria, it is not the root cause. Saliva plays a crucial role in maintaining oral hygiene, and without sufficient saliva, bacteria can proliferate, but they are initially the source of the odor. Certain foods, such as garlic and onions, can also contribute to bad breath but typically only temporarily. Their strong flavors are absorbed into the bloodstream and can affect breath after they are metabolized. Similarly, smoking can lead to a variety of oral health issues, including dry mouth and increased bacterial growth; however, it is the bacteria that directly cause the most persistent halitosis. Thus, while all the options contribute to bad breath in some way, the primary underlying cause is indeed the buildup of bacteria.