When the teeth had fallen out, Varuṇa returned and said to Hariścandra, “Now the animal’s teeth have fallen out, and you can perform the sacrifice.” But Hariścandra replied, “When the animal’s teeth grow in again, then he will be pure enough to be sacrificed.”
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
पशोर्निपतिता दन्ता यजस्वेत्याह सोऽब्रवीत् । यदा पशोः पुनर्दन्ता जायन्तेऽथ पशुः शुचिः
paśornipatitā dantā yajasvetyāha so'bravīt | yadā paśoḥ punardantā jāyante'tha paśuḥ śuciḥ
SB 9.7.13