Matsya Purana — Bhīma-Dvādaśī
नैयग्रोधं दन्तकाष्ठम् अथवा खादिरं बुधः गृहीत्वा धावयेद्दन्तान् आचान्तः प्रागुदङ्मुखः //
naiyagrodhaṃ dantakāṣṭham athavā khādiraṃ budhaḥ gṛhītvā dhāvayeddantān ācāntaḥ prāgudaṅmukhaḥ //
After performing ācāmana (purificatory sipping of water), a wise person should take a toothbrush-stick of nyagrodha (banyan) or khadira (acacia catechu) and clean the teeth while facing east or north.
This verse does not discuss Pralaya; it focuses on āhnika (daily purification) practices that sustain dharma in ordinary life.
It prescribes a basic discipline of cleanliness and ritual purity—ācamana followed by dental cleansing—reflecting the expected self-governance and sāttvic conduct of householders (and by extension rulers) in the Matsya Purana’s dharma framework.
Ritually, it specifies correct materials (nyagrodha/khadira twigs) and proper orientation (facing east or north) for dantadhāvana after ācamana—details typical of Purāṇic procedural rules rather than Vāstu or temple architecture.