may be but as my family friend also told me and an another dentist also as i have to make my teeth checkup once as there colour is yellow whatsoever i do so he told that its permanently yellow and that time he too told about the same.and no one do changes brush in one month.
Even i too change my brush every month as i have to do it as bristles of the brush becomes useless if i continue using it after a month. :)
