Can you tell me is chocolate or sweet bad/good for your teeth in long term?

Depends on you: Who doesn't like chocolate? I know i do. The important thing is to understand why sweets are damaging to the teeth. It's not the sugar that causes cavities, it's the bacteria already present in all our mouths that utilize the carbohydrate (sugar) and produce acid that eats into your enamel causing cavities and decay. So, eat all the sweets you want, but be sure to brush and floss directly after.