Abu Hurairah Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said: Were it not (for the fear) of overburdening my Ummah, I would have ordered them to (brush their teeth with) Siwak at every Salat. (Muslim: 589)
Note: Siwak or Miswak is a natural tooth brush prepared from the
roots or branches of various trees and bushes. The most common and
beneficial is that of the root of the Salvadora Persica, a wild desert
plant known in Arabic as Arak, and in Urdu as Peelu.