Answer

In Jain tradition, during upvaas many observant people avoid brushing teeth in the usual way, especially with toothpaste or water, because upvaas involves strict restraint from consumption and indulgence.

Ancient Jain practice emphasized saṃyam — self-restraint — so oral cleaning during upvaas was generally kept very minimal, if done at all.

Explanation

Traditionally, Jain upvaas means not taking food, and in stricter forms, not taking water either. Because brushing usually involves:

• using water,
• risk of swallowing water,
• use of flavored substances,
• possible harm to tiny living beings,

many Jains avoid normal brushing on upvaas days.

In older times, people often used natural methods like rinsing, herbal sticks, or simple cleaning practices in daily life. But during strict fasting, the focus was on reducing bodily attention and maintaining spiritual discipline.

Spiritual Understanding

The purpose of upvaas is not only to avoid food, but to move closer to the soul by reducing attachment to the body. So even small habits like taste, freshness, comfort, and routine are restrained.

However, practices may vary by Jain sect, family tradition, health condition, and the type of fast.

Takeaway

Ancient Jain fasting practice generally favored avoiding ordinary tooth-brushing during upvaas, especially if water or taste was involved. The deeper idea is restraint, awareness, and care not to break the purity of the fast.