Can the teeth under bonding get cavities or decay?

Probably not good to eat.  Also, probably will not work and in fact, it it is a cyanacrylate (spelling?) glue, like SuperGlue, it dissolves in water.

Aisha,    If you're in pain, you should be able to explain to your orthodontist that you need to be seen because your retainer is cutting your tongue. That is usually a pretty quick fix for them.    In the meantime, you can buy orthodontics wax at the grocery store...

Small changes can usually be fixed by polishing or contouring the teeth.  Bite forces create stress that bonding normally cannot tolerate, so porcelain is better.  However, porcelain is not bulletproof.  This sounds more complicated than you are aware, so be sure to seek and...

Difficult to tell from you photo's, your central incisors look nice.  I can't see differences in gum levels, need to show more gum tissue above where teeth end.  I would recommend that you check out EasySmileVeneers(soon to be called ProVeneers).  They are a breakthrough in...

A permanent crown is the answer to your question. It is the most predictable answer to your question. . This will have you chewing at a 100%. It sounds like a filling will not be enough for that tooth. You may also need a Root canal on the tooth depending on the extension of the fracture.

Sorry this is happening, it must be frustrating.  There are a few factors that may be impacting the strength of the bonding.  One is the eroded enamel and possible presence of acid which could be affecting the bond.  Another is the steps and technique taken to actually...