KIEL, Germany -- Teeth can become discolored for a variety of reasons -- including consumption of dyes from foodstuffs such as coffee, tea, cola drinks and tobacco, DPA quoted the Schleswig- Holstein Chamber of Dentists as saying.

But illnesses and medication can also be a cause.

Teeth also tend to change color with advancing age.

But the chamber recomends that people dissatisified with the color of their teeth should not take the matter into their own hands and whiten them with over-the-counter products.

That could cause damage.

Instead they should consult a dentist who should find out the cause of the discoloration and then treat it.