ENOfficial
Hudhaifa said that when the Prophet (ﷺ) got up to pray during the night he cleansed his mouth with the tooth-stick. (Bukhari and Muslim.)
Source: sunnah.com
Other translations
Arabic
وَعَنْ حُذَيْفَةَ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا قَامَ لِلتَّهَجُّدِ مِنَ اللَّيْلِ يَشُوصُ فَاهُ بِالسِّوَاكِ
sunnah.com