The Miswak is the natural equivalent of the toothbrush. It is a short twig with frayed bristles that is used to brush the teeth and it is made from the twigs of the Salvadora persica (Peelu or Arak) tree. The Prophet Muhammad ﷺ highly recommended using the Miswak to clean the teeth. The Miswak has a natural anti-bacterial effect and decreases tooth decay and improves the odour of the mouth. It is recommended to use the Miswak (even if you have a modern toothbrush) before praying as it is stated in sayings of Prophet Muhammad ﷺ. The stick is obtained from a plant called Salvadore Persica that grows around Mecca and the Middle East area in general. 
Prophet Mohammed ﷺ recommended its use in various ahadith:Narrated Abu Hurairaرضي الله عنه, Allah’s Apostle Prophet Muhammad ﷺsaid, “Were I not afraid that it would be hard on my followers, I would order them to use the siwak (as obligatory, for cleaning the teeth) Sahih Bukhari Volume 9, Book 90, Number 346:
Narrated Hudhaifa رضي الله عنه, Whenever the Prophet Muhammad ﷺ got up for Tahajjud prayer he used to clean his mouth (and teeth) with Siwak. Sahih Al Bukhari Volume 2, Book 21, Number 237:
Abu Hurayrah رضي الله عنه, who reported that the Prophet Muhammad ﷺ 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.” Sahih Al Bukhaari, 2/299 and Muslim, 1/151).
A 2003 scientific study comparing the use of Miswak with ordinary toothbrushes concluded that the results clearly were in favor of the users who had been using the Miswak , provided they had been given proper instruction in how to brush using it. The World Health Organization (WHO) recommended the use of the Miswak in 1986 and in 2000 an international consensus report on oral hygiene concluded that further research was needed to document the effect of the Miswak .
Chemical analysis of S. persica Miswak has demonstrated the presence of β-sitosterol and m-anisic acid ( Ezmirly et al., 1979 and Ray et al., 1975); chlorides, salvadourea, and gypsum; organic compounds, such as pyrrolidine, pyrrole, and piperidine derivatives (Galletti et al., 1993); glycosides, such as salvadoside and salvadoraside (Kamel et al., 1992); and flavonoids, including kaempferol, quercetin, quercetin rutin, and a quercetin glucoside (Abdel-Wahab et al., 1990). The roots and bark of the S. persica tree are composed of 27% ash; a high ratio of alkaloids, such as salvadorine and trimethylamine; chlorides and fluorides; moderate concentrations of silica, sulfur, and vitamin C; and small quantities of tannins, saponins, flavonoids, and sterols ( Akhtar and Ajmal, 1981, Al Lafi and Ababneh, 1995 and Farooqi and Srivastava, 1968). High amounts of sodium chloride and potassium chloride were noted, along with other sulfur-containing organic substances (salvadourea and salvadorine) (Dorner, 1981).
In many developing countries, chewing sticks are often used as the sole oral cleaning device. Oral hygiene maintenance through the regular removal of dental plaque is an essential factor in the prevention of dental caries and periodontal disease. Several explanations for the cleansing effectiveness of S. persica Miswak have been put forward, including (a) the mechanical effects of its fibers, (b) the release of favorable chemicals from the chewing stick while in use, or (c) a combination thereof. However, the lack of studies reporting the time, duration, and frequency of S. persicaMiswak use prevents meaningful assessments of its mechanical cleaning effects on oral health (Hardie and Ahmed, 1995). 
1. Miswak strengthens the gums and prevents tooth decay.
2. Miswak assists in eliminating toothaches and prevents further increase of decay which has already set in.
3. Miswak creates a fragrance in the mouth.
4. Miswak is a cure for illness.
5. Miswak eliminates bad odors and improves the sense of taste.
6. Miswak sharpens the memory.
7. Miswak is a cure for headaches.
8. Miswak creates lustre (noor) on the face of the one who continually uses it.
9. Miswak causes the teeth to glow.
10. Miswak strengthens the eyesight. 
Dr. ‘Abd-Allaah ‘Abd al-Razzaaq al-Sa’eed says:
It is indeed a miracle of the trustworthy and unlettered Messenger (blessings and peace of Allah be upon him), who said: it was narrated from ‘Aa’ishah (may Allah be pleased with her) that the Prophet (blessings and peace of Allah be upon him) said: “Siwaak is purifying for the mouth and pleasing to the Lord.” Narrated by al-Nasaa’i (hadeeth no. 5). Al-Bukhaari narrated it as a mu’allaq majzoom report in Kitaab al-Sawm, Bab Siwaak al-Ratab wa’l-Yaabis li’l-Saa’im. 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). See al-Silsilah al-Da’eefah by al-Albaani (no. 5276).