Craze line or crack? Does that mean they are cracks and Invisalign could make them worse? (photo)

I have NEVER heard of Invisalign causing any such damage to teeth!  I believe you have been mis-informed as Aligner tooth straightening is probably the most gentle method of tooth movement developed to date!Tooth "cracking" or haze lines are usually a result of dental bruxism, night time tooth grinding, where there is tooth vs tooth/enamel vs enamel traumatic biting of teeth driven by the masseters and sometimes felt as tension headaches by the temporalis muscle.  This happens most to "tight" teeth not loose moving teeth which is what occurs with aligners.If you think you are grinding your teeth at night, having headaches, have wear on the edges of your front teeth or have popping clicking jaw joints, you should have a thorough pre-treatment evaluation which could include a sleep study if deemed necessary.