The Messenger of Allah ﷺ said, "Were it not that I would burden my community, I would have commanded them to use the siwak before every prayer."
حدثنا عبدة حدثنا محمد بن عمرو عن أبي سلمة
قال رسول الله ﷺ لولا أن أشق على أمتي لأمرتهم بالسواك عند كل صلاة
Its isnad is sahih. Ubayda, with a fatha on the ayn, is Ibn Humayd, with a damma on the ha. The hadith is an abridgment of 7335 and 7338. See also 7504.