1. The Prophet (peace and blessings of Allaah be upon him) said: “Siwaak is purifying for the mouth and pleasing to the Lord.”
Bukhaari in his Saheeh, 2/274; Ahmad, 6/47 and al-Nisaa’i, 1/50. It was classed as saheeh by al-Mundhiri in al-Targheeb wa’l-Tarheeb (1/133) and classed as hasan by al-Nawawi in al-Majmoo’ (1/267). Its isnaad is saheeh, see al-Irwa’ 1/105.
2. The Prophet (peace and blessings of Allaah be upon him) said: “Were it not for the fact that I did not want to make things too hard for my ummah, I would have commanded them to use the siwaak at every time of prayer.”
(Reported by al-Bukhaari, 2/299 and Muslim, 1/151). According to another report narrated by al-Bukhaari, he said: “…at every time of making wudoo’.”
3. ‘Aa’ishah was asked what the Messenger of Allaah (peace and blessings of Allaah be upon him) did when he first came home. She said, “When he entered his house, the first thing he would do was to use the siwaak.” (Reported by Muslim, 1/220)
4. Hudhayfah ibn al-Yamaan (may Allaah be pleased with him) reported that when the Prophet (peace and blessings of Allaah be upon him) got up during the night, he would clean his mouth thoroughly with the siwaak. (Reported by al-Bukhaari, 1/98 and Muslim, 1/220)
5. Imaam al-Nawawi reported that the respectable scholars were agreed that use of the siwaak is sunnah and is encouraged (mustahhab). One of the signs of its importance is the fact that some of the salaf such as Ishaaq ibn Raahawayh, thought that it was fard.
6. . Dr. Muhammad Sa’eed al-Jareedli – head of the Mouth Disease department at Cairo University – said: “The siwaak is many times better than the toothbrush and toothpaste in chemical and mechanical terms. After carrying out research he found that the substance which is in the siwaak kills germs and heals our mouths from disease. By itself it can take the place of the toothbrush and toothpaste because of the numerous substances it contains which are superior to those contained in toothpaste. Similarly, strong, gentle natural fibres work better than the fibres of the toothbrush and do not damage the gums. They also effectively remove what is left in our mouths and clings to our teeth of leftover food, which can cause disease and damage to the mouth and teeth. Up until today, in our civilised world, there is no toothpaste that contains the substances contained in the siwaak. Similarly, it says in the weekly magazine American Dentist that most of the toothpastes used in the United States of America are not good or healthy…”
And Allah knows best.