Useless bottles

So I chose Avent and my little girl did too, however when she got teeth and started biting through teats it was almost tragic that you had changed the shape and she hates them, I searched long and hard and finally found a Nuby bottle that was like the old Avent teat smooth and perfect. What is up with the new teats and the indentation around the drinking hole? I now have a marvellously large collection of expensive baby bottles that can't be used again. She is outgrowing bottles now so we have 2 Nubies that we rotate. It has been an inconvenience and as a sinlge Mom the extra expense at this stage of the game was unappreciated.