Is brushing your teeth during the day on Ramadan, allowed?

Praise be to Allah, the Lord of the World; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

A fasting person may use a Miswak (tooth stick) anytime during his fast. It does not affect his fast since the Prophet urged using it without assigning it to a particular time. One should take all precautions to prevent anything reaching his throat.
Allah knows best.