when the Messenger of Allah (may Allah's peace and blessings be upon him) used to get up at night, he would cleanse his mouth with the tooth-stick.
[Sahih/Authentic] - [Al-Bukhari and Muslim
Original Hadith
"«كان رسول الله -صلى الله عليه وسلم- إِذَا قَام من اللَّيل يُشُوصُ فَاهُ بِالسِّوَاك».
[صحيح.] - [متفق عليه.]"