I'm Currently Using Invisalign and I Have Noticed That my Front Teeth Are Becoming a Bit Transparent?

Hi,

Invisalign, on its own does not cause erosion of enamel.  Nor does it cause teeth to become thinner.  There is a procedure called interproximal reduction or filing of teeth, which takes away a small amount of enamel, but on the surfaces of teeth which contact the neighbouring tooth.  This also, will not cause teeth to become transparent.  

If you drink lots of pop, fruit juice or anything that is acidic with the aligners in your mouth, and do not rinse or wash them out regularly, you could be exposing your teeth to this acid, which theoretically in turn could cause erosion.  But as long as you follow the instructions given to you by your Orthodontist, you should not be experiencing any thinning or wearing away of the teeth using Invisalign.