The Prophet (SAWA) said in his advice to Imam Ali (AS), 'You must brush your teeth at every ablution.
رسولُ اللهِ (صَلَّيَ اللهُ عَلَيهِ وَ آلِهِ) ـ في وصيَّتِهِ لعليٍّ (عَلَيهِ الّسَلامُ) ـ: علَيكَ بالسِّواكِ عِندَ كُلِّ وُضوءٍ.
Similar narrations
Man Lā Yaḥḍuruh al-Faqīh #111Hadith.113 - The Prophet (sw), said in his will to Imam Ali ibn Abi Talib (as):
"O’ Ali (as), make sure to use siwak (toothstick) before...