Two front teeth on backside (not visible) have a small chip. My dentist recommends bonding.

Hello,When you have a teeth with a small chip, is good to take care of it. Once you got a chip on a teeth, it can get bigger by the time as  futher damage. I hope it help you. Good luck!. 

Ideally you would have these areas of chipping bonded.  Practically it makes little difference.  The bigger question would be, "Why are the teeth chipping?"  Chipping of front teeth is often related to chewing patterns. This can sound quite complicated, but to a dentist who really understands function of jaws (called "Occlusion") it would make perfect sense.  To be more specific, when we chew our lower teeth trace out an eliptical motion.  If the teeth fall within this eclipse, they will invariably chip; so the better solution would be to orthodontically tip the edges of these teeth out of the chewing pattern.