حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ حُصَيْنٍ، قَالَ سَمِعْتُ أَبَا وَائِلٍ، يُحَدِّثُ عَنْ حُذَيْفَةَ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا قَامَ مِنَ اللَّيْلِ يَشُوصُ فَاهُ بِالسِّوَاكِ .
It was narrated that Hudhaifah said: "When the Messenger of Allah (PBUH) got up to pray tahajjud at night, he would brush his teeth with the siwak. Translation Not Available
Book Ref: Sunan An Nisai Book 20 Hadith 1622
Web Ref: Sunan An Nisai Vol 2 Book 20 Hadith 1623