Ask the Dentist!


I see crack lines in my front teeth! What do I do?

I love make up mirrors. With the combination of bright light and magnification, every minute detail is visible, especially on and in the front teeth. I can always tell who uses one when they ask me to check something I can’t see without my magnification loops on. Although things tend to look pretty bad when magnified, not all things are as bad as they look.

Craze lines

Craze lines typically appear as vertical lines that are visible on the surface of teeth when light hits the surface at just the right angle. They are most easily seen on the front teeth since front teeth are not as thick as the back teeth. I often compare craze to lines that are visible on the surface of aged porcelain cups. Enamel is the hard outer covering of teeth and is structurally much like glass. When enamel is subjected to extremes in temperature and pressure, the surface will form craze line. Hot coffee, cold ice water or teeth clenching will cause these lines to form. Add this up over many years and you get a craze line.

I will typically not recommend any direct treatment for craze lines but if a clenching or grinding habit is present I will recommend a splint to wear between the teeth at night and as needed during the day.

Crack lines

Crack lines are similar to craze lines, except deeper. While craze lines may only be visible when light hits a certain way, crack lines are usually always visible, no matter what the lighting. Crack lines form due to the same causes as craze lines but the crack will extent into the deeper parts of the tooth beyond the enamel. When cracks reach this depth, the tooth is in jeopardy of breaking at any moment, even while eating soft foods. Bread seems to be the most common food to break teeth. If bread breaks a tooth the crack was pretty deep already. The problem with crack lines is the unpredictable nature of when they will give way. I routinely recommend treatment for teeth with really deep crack lines for this reason. Teeth never seem to break at the right time. It seems to always happen on the weekend or on vacation. Crack lines can also allow bacteria to reach the deeper parts of the tooth leading to cavity formation.


Deep crack lines. 


Crack lines (left) vs. craze lines (right). 

If you’re not sure what you’re seeing in the mirror is a craze or crack, give us a call: (225) 926-4203. 


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