My baby is 17mths old and has been on pacifier since 4 mths old. He only uses when he sleeps but I noticed that he is starting to have bugs bunny teeth. Is it because of the pacifier?

Like what Nooraini mentioned, pacifier use during the first few years of a baby's life is unlikely to cause any permanent "damage" to the baby's teeth. However, if the habit continues after the baby teeth has fell off and the permanent teeth start emerging, then there may be some impact on the teeth. In fact, thumb sucking will have the same effect. But at 17 months, you shouldn't be too worried. Usually, a child will wean off pacifier (or thumb sucking) before the permanent set of teeth starts growing.