In the Anguttara Nikaya there is a short sutta in which the Buddha describes the benefits of using a tooth stick (dantakaṭṭha), the ancient Indian equivalent to our tooth brush. The advantages of regular brushing, the Buddha said, include that it is that it is good for the eyes, the breath does not have a bad smell, the taste buds are cleaned, bile and phlegm do not mix with the food, and food becomes more palatable (A.III,250). In my book Nature and the Environment in Early Buddhism I tried to identify the tree or trees that might have been used to make these tooth sticks, but without success. I conjectured that they were probably Streblus asper and Salvadora persica both now called the Toothbrush Tree, Azadirachta indica or Neem, and (Acacia Arabica i.e. Babul, mainly because village people in Bihar and Uttar Pradesh use them today.
The monk Yijing who was in India in the 7th century and on his return to China wrote an account of his trip, advised his readers to follow Indian dental hygiene practices. He wrote: ‘The shortest (tooth stick) is not less than eight finger-lengths long, resembling the little finger in size. Chew one end of the wood well and then brush the teeth with it…After having used the wood for brushing the teeth, split and bend it and scrap the tongue…A thin flat piece of bamboo or wood, the size of the surface of the little finger and sharpened at one end, may be used as a toothpick to clean broken teeth…Twigs of a bitter, astringent, or pungent taste, the end of which may become cotton-like after being chewed are best for using as tooth wood…Toothache is almost unknown in India because the people there use tooth wood.’ While Yijing was quite detailed about how to use a tooth stick he did not mention what wood they were made of.
Interestingly, the Mahisasaka Vinaya lists the trees that should not be used as tooth sticks without mentioning which should be. Those to be avoided are Toxicodendron vernicifluun, Bassia latafolia (Pali madhuka), Ficus religiosa (Pali assattha, the Bodhi Tree) and two others called dushu and saka, the identification of which are unclear. But just recently I discovered that the Susruta Samhita (circa 2nd cent. BCE to 2nd cent CE) has a section on oral hygiene and mentions four types of wood that can be used for tooth sticks – they are Neem (Pali nimba), Acacia catechu (Pali khadira), Bassia latafolia (Pali madhuka) and Pongamia galbra (Pali karanja). Neem is widely used in India today and probably was during the Buddha’s time too.