It was narrated that Hudhaifah said:
"Whenever the Messenger of Allah got up for prayer at night to pray Tahajjud (night optional prayer), he would clean his mouth with the tooth stick." (RU)
English reference (RU): Vol. 1, Book 1, Hadith 286 (RU)
Arabic reference (RU): Book 1, Hadith 301 (RU)