Teeth whitening is a routine dental procedure. While some people prefer taking professional help for it, others resort to at-home whitening products. Whatever the method may be, teeth whitening helps people in getting their bright smile back. Apart from removing the tough stains from your teeth, whitening may also bring out the craze lines.

Craze lines should not be confused with cracked teeth. These lines are always present but only become visible after a whitening session.  

If you are wondering that after a whitening session what are these noticeable vertical lines on teeth? then you should first try to understand its causes:

  • Thinning tooth enamel: The most common cause of craze lines is the thinning of enamel or the outer covering of teeth. Excessive force and pressure on teeth biting nails or grinding teeth can cause white lines to appear. Whitening brings out these light lines as a result of which the thinner part of enamel becomes visible.
  • Hypocalcification: Hypocalcification precedes the formation of cavities. It is the demineralization of teeth due to unkempt dental hygiene. The acid produced by the bacteria that survive on the leftover food in your mouth may cause the teeth to weaken. Whitening can bring out the lines caused due to demineralization which appear as white craze lines. Cutting down on sugary food can help solve this issue.
  • Dehydration: The bleach used for whitening teeth contains hydrogen peroxide. However, if not used too often or in too-high concentrations, this is just a temporary issue and doesn’t cause any long-term harm to your oral health.

The appearance of white lines may be unsettling for many. The lines stand out from the rest of the teeth, making them look bad.


If the cause of craze lines is dehydration of teeth, you do not have to be concerned. They will automatically fade out with the new shade of the teeth. If the lines persist, you should consult a dentist as the cause may be hypo calcification or thinning enamel. White lines also increase the risk of staining or decolourisation of teeth.

Demineralization or thin enamel may prove to be harmful to your teeth. It significantly increases the chances of developing cavities as the protective layer of the teeth is destroyed gradually. This can be avoided by following a proper oral hygiene routine for keeping up your dental health. Avoiding any activity that puts undue pressure on your teeth like opening a soda can with the teeth can also help you stay away from these craze lines.

Vertical lines on your teeth after whitening may either be an indication of a potential dental problem or maybe a temporary side effect.  Smoking cigarettes or other tobacco products may also be a cause for these lines. It is highly probable that the lines were always present but were not noticeable due to the yellowing of the teeth. Whatever the cause of craze lines might be, if you have them on your teeth you might need to consult your dentist for treatment options.