Is there a scientific explanation for the materializations of vibhuti and other small objects such as rings, necklaces by many saints?
No, even they say don’t give much importance to it. It is nothing. It is just a technique. There are many such vidyas (techniques) to do those things. You don’t have to be enlightened to do those things.
What is much more important than bringing a ring from there to here is bringing a change in the mind, and a change in one’s life. That is important.