As enamel naturally wears down with age, the underlying dentin (which is yellowish) becomes more visible.

Genetics

Some people naturally have thicker or whiter enamel, while others have slightly yellower dentin—color can run in families.

Medications

Certain antibiotics (like tetracycline when taken in childhood), some antihistamines, and blood pressure medications can cause tooth discoloration.

Excessive Fluoride

High fluoride exposure in early childhood can cause dental fluorosis, leaving white spots or streaks that sometimes appear yellowish over time.

How to Prevent Yellowing

Brush twice a day with fluoride toothpaste and floss daily.

Rinse after staining foods/drinks and consider using a straw for coffee/tea.

Quit smoking or avoid tobacco.

Regular dental cleanings (every 6 months) to remove plaque and tartar.

Limit sugary and acidic foods that weaken enamel.

Consider whitening options (professional whitening, at-home trays, or whitening toothpaste).