Reference: Sharh ‘Umdatil-Fiqh – Tape No.5, Question No.3
Question: Is it [from] the Sunnah to brush the teeth with a miswaak before starting the wudhoo, or whilst doing so?
Response: No. [It is from] the Sunnah [to do so] before the wudhoo, when you are about to do wudhoo, yes. [And take note, it is from] the Sunnah to brush [your teeth] with the left hand, because brushing [is done] to remove the harmful particles; brushing [is done] to remove the harmful particles from the mouth [and teeth].