Q: I hear people saying that using Miswak (tooth-cleansing stick) in the Masjid is impermissible. Is this true?
A: Using the Miswak is an affirmed act of Sunnah. It should be used when necessary upon performing Wudu’ (ablution), Salah, reciting the Qur’an, changing the mouth smell, etc.
It may be used inside or outside the Masjid, as no text supports the prohibition of using it inside the Masjid when necessary. Moreover, it finds further support in the general meaning of the following Hadith, “Were it not for the fear that it might be hard for my Ummah (nation), I would have ordered them to use Miswak for every Salah.” 
However, a person should be careful not to overdo the Miswak in the Masjid lest they should vomit or bleed in the Masjid.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.
The Permanent Committee for Scholarly Research and Ifta’
Chairman – Shaykh Abdul-`Aziz ibn `Abdullah ibn Baz
 Al-Bukhari, Sahih, Book in Friday, no. 887; Muslim, Sahih, Book on purification, no. 252; Al-Tirmidhy, Sunan, Book on purification, no. 22; Al-Nasa’y, Sunan, Book on purification, no. 7; Abu Dawud, Sunan, Book on purification, no. 46; Ibn Majah, Sunan, Book on purification and its Sunan, no. 287; Ahmad ibn Hanbal, Musnad, vol. 2, p. 433; Malik, Al-Muwatta*, Book on purification, no. 147; and Al-Darimy, Sunan, no. 683.
Fatwas of the Permanent Committee>Group 1>Volume 6: Salah 1>Salah>Rulings related to the Masjids>Using Miswak in the Masjid