There's no perfect toothbrush, but some toothbrushes are less perfect than others, and sadly, a few of them aren't even what they claim to be. Here are a few disappointing facts I have learned recently about other companies' toothbrushes.
Source: The Truth About Your Biodegradable Bamboo Toothbrush – My Plastic-free Life
A very interesting assay about the perfect toothbrush – unfortunately such thing does not seem to exist. However I have to admit, compared to the rest of the plastic we are usually using, I would consider some bristles as minor, so I guess a bamboo toothbrush is much better than a plastic one.