you dont need to worry about overgrown deeth with FW dwarf puffers. However,in most other puffers, if the teeth got too long, they could potentially starve to death. this would mean you would have to clip the teeth yourself or feed snails often. But if you are getting dwarf puffers, you dont need to worry about keeping the teeth worn down. snails do make a nice puffer treat though.
__________________
Current setups: 1800 gallon koi pond, 10 gallon planted, 150 gallon reef, other FOWLR tanks