A tiger cannot be vegetarian. They are pure carnivores meaning they only eat meat. Tigers are at the top of the food chain. They mainly eat large mammals, such as pigs, deer, antelope, buffalo, and gaur.
No, its teeth are geared for biting into prey. It's like humans using canine teeth to bite into meats. Sharp tiger teeth are meant for biting through layers of skin and flesh and fat. Not for biting and crunching down leaves. That requires flat teeth.