Shiva Purana
अलाभे दंतकाष्ठानामष्टम्यादिदिनेषु च ॥ अपां द्वादशगण्डूषैः कुर्यादास्यविशोधनम् ॥ ४ ॥
On the eighth and other days whenever tooth-brush twig is not available he shall gargle twelve times and clean the teeth.
english translation
alAbhe daMtakASThAnAmaSTamyAdidineSu ca ॥ apAM dvAdazagaNDUSaiH kuryAdAsyavizodhanam ॥ 4 ॥
hk transliteration by Sanscript