Anas (May Allah be pleased with him)reported:
The Messenger of Allah (pbuh) said, "I stress upon you to use Miswak (tooth-brush)."
[Al-Bukhari].
وعن أنس رضي الله عنه، قال: قال رسول الله صلى الله عليه وسلم : "أكثرت عليكم في السواك" ((رواه البخاري)).
Studies
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.[2] 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.[3]
Dr. Rami Mohammed Diabi,[4] who spent more than 17 years researching the effects of miswak on health, and especially its anti-addiction effects on smokers (curative and preventive sides), has opened a field of science and research with his last publication: "Miswak Medicine Theory" or Sewak Puncture medicine[5] which led him to what is called Beyond Sewak: World of Science and Research.[6]Miswak also is contributing in the fight against desertification,[7] thereby affecting our environment and global climate.
8. Toothbrush
According to Hassani, the Prophet Mohammed popularized the use of the first toothbrush in around 600. Using a twig from the Meswak tree, he cleaned his teeth and freshened his breath. Substances similar to Meswak are used in modern toothpaste.
Sources;
Muslim inventions that shaped the modern world - CNN.com
Miswak - Wikipedia, the free encyclopedia