Matsya Purana — Kṛṣṇāṣṭamī Vrata: Monthly Śiva-Names
मार्गशीर्षाषाढमासाभ्यां द्वाभ्यां द्वाभ्यामितिक्रमात् एकैकं दन्तपवनं वृक्षेष्वेतेषु भक्षयेत् //
mārgaśīrṣāṣāḍhamāsābhyāṃ dvābhyāṃ dvābhyāmitikramāt ekaikaṃ dantapavanaṃ vṛkṣeṣveteṣu bhakṣayet //
Beginning with the months Mārgaśīrṣa and Āṣāḍha, proceeding in due order by pairs of months, one should each time chew a single tooth-cleansing twig (dantapavana) from those specified trees.
This verse does not discuss pralaya; it focuses on disciplined ritual hygiene—monthly sequencing for using a dantapavana (chewing twig) as part of purification-oriented observance.
It supports the householder’s (and ruler’s) duty to uphold śauca (cleanliness) and regulated conduct: even routine acts like dental cleansing are framed as dharmic discipline performed according to calendrical order.
The ritual significance is bodily purification (śauca) via dantapavana, scheduled by months in pairs; it reflects the Purāṇic emphasis that correct timing and prescribed materials are integral to vrata practice.