The Prophet ﷺ said, "Why do I see you coming to me with unkempt hair? Would it not be difficult for my Ummah (nation) if I were to impose the use of Siwak (tooth-cleaning twig) on them, just as I have made Wudu (ablution) obligatory upon them?"
أَتَوْا النَّبِيَّ ﷺ أَوِ أتِيَ فَقَالَ مَا لِي أَرَاكُمْ تَأْتُونِي قُلْحًا اسْتَاكُوا لَوْلا أَنْ أَشُقَّ عَلَى أُمَّتِي لَفَرَضْتُ عَلَيْهِمُ السِّوَاكَ كَمَا فَرَضْتُ عَلَيْهِمِ الْوُضُوءَ