EDIT: I misread your post and understood that you were talking about the fangs intead of the growl, haha. Sorrry! But I will maintain my original post in case it's useful.
But his point is kind of true, the fangs that Yamato grew have very little to do with the ones of that dragon: the dragon's are all very long, thin and of the same size, while Yamato has shorter, pointy fangs with prominent canines, which is exactly how Oda draws a tiger's jaw:
Yamato's fangs look more like those of Kaido's Eastern dragon, that's true, but his are still longer and thinner than Yamato's, also more "separated" from each other, similar to the Western dragon's. Of course this could be just an aesthetic choice and we can't say anything for sure, but Yamato's teeth look more like those of a tiger than a dragon.