About Relic of the tooth of the Buddha

The Relic of the tooth of Buddha is venerated in Sri Lanka as a cetiya relic of Gautama Buddha, on whose teachings Buddhism was founded.
Relics of buddha from the Supreme Patriarch of Thailand

Buddhist relics – The ashes of spiritual Masters

Śarīra is a generic term referring to Buddhist relics, although in common usage it usually refers to pearl or crystal-like bead-shaped objects that are purportedly found among the cremated ashes of Buddhist spiritual masters. Relics of the Buddha after cremation are termed dhātu in the Mahaparinibbana Sutta. Śarīra are held to emanate or incite 'blessings' and 'grace' within the mindstream and experience of those connected to them. Sarira are also believed to ward off evil .
The Ruwanwelisaya stupa, built by the Sri Lankan King Dutugemunu

Theravada – Buddhism’s oldest existing school

is the most commonly accepted name of Buddhism's oldest existing school. The school's adherents, termed Theravādins, have preserved their version of Gautama Buddha's teaching or Buddha Dhamma in the Pāli Canon for over a millennium. The Pāli Canon is the most complete Buddhist canon surviving in a classical Indian language, Pāli, which serves as the school's sacred language and lingua franca. In contrast to Mahāyāna and Vajrayāna, Theravāda tends to be conservative in matters of .