Siwak (to clean the teeth with Siwak which is a tooth-brush in the form of a pencil from the roots of the Arak tree Sahih al-Bukhari 245
Arabic hadith text
حَدَّثَنَا عُثْمَانُ، قَالَ حَدَّثَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ أَبِي وَائِلٍ، عَنْ حُذَيْفَةَ، قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلمإِذَا قَامَ مِنَ اللَّيْلِ يَشُوصُ فَاهُ بِالسِّوَاكِ.
Translation
Narrated Hudhaifa
Whenever the Prophet (ﷺ) got up at night, he used to clean his mouth with Siwak.