Take it to the guinea pig dentist
Guinea Pigs have 20 teeth. (:
yes. a guinea pigs teeth are always growing.
They need teeth to eat.
Guinea Pigs are Rodents, and their teeth are always growing. Provide them with materials to gnaw on, and they will take care of their own teeth.
No.
YES
Their teeth are about the same size as a rats.
guinea pigs have 24 teeth
Its teeth might be to long and the result is pain as it eats
If a guinea pig losses it's front teeth it could chew with their back teeth.
Guinea pigs don't actually get itchy teeth. They are rodents, and this means their teeth never stop growing. To keep their teeth worn down, they will gnaw the wooden edges of their cage. Maybe this is what you interpret as having itchy teeth. If you don't give your guinea-pig pieces of untreated wood to gnaw on, it's possible for their teeth to grow so long that they can't eat.
Guinea pig's teeth continuously grow but you can give them small logs or hay for then to graze them on.