check with the ped. dentist to see what the life expectancy is on the bonding, and if it's the type that's intended to be used "just" until the kid is old enough for the more permanant type.
i say this b/c dd had a bike accident several years back that damaged one of her front teeth. the tooth could be saved but a portion was missing. the ped. dentist did bonding but advised us that because of the nature of kids growing and their facial structure still changing the type that's commonly used is not intended for long term use, and that a more permanant type would be appropriate when dd hit adulthood.
dd's had to have the bonding redone on a few occasions although she's pretty careful to avoid the foods she's been warned off of (another issue to take into consideration with a kid-will they follow the guidelines for what can/should be avoided food wise) but kids being kids she's spaced and bitten too hard into one food or another-and the cost of replacement is not cheap. it's not cheap but at least in our case b/c it was due to an injured tooth originaly at least a portion of it's covered by insurance. if it were a purely cosmetic bonding our insurance would'nt cover a penny of it.