There are many causes of oral odor, with pulpitis and periapical diseases being the primary reasons. These conditions are bacterial infections, and the bacteria in the decayed cavities may break down proteins in saliva, food proteins, and sugars, leading to the production of amine compounds, which contribute to the development of oral odor.

In addition to pulpitis and periapical diseases, oral odor can also be related to a person’s oral hygiene habits, such as whether they brush their teeth regularly. If one does not brush after each meal or rinse their mouth after eating, food residues in the mouth can be broken down by oral bacteria, resulting in unpleasant smells.

Furthermore, periodontal disease, which is also caused by specific pathogenic bacteria, can lead to oral odor. Periodontal disease is often caused by anaerobic bacteria that break down proteins, releasing odorous molecules, which can result in bad breath in some patients.

Additionally, systemic health conditions such as diabetes and kidney disease may also cause exhaled breath to carry an unpleasant odor.