Hello Mrs.Mano,
About sotrupai, give you the detail what I read in that magazine.
In order to stop the tooth decay from spreading, take 1 portion of pepper powder and the equal portion of sotrupai and powder them. Use this powder to brush teeth and the water from the decayed tooth will come out and this is how, it will not spread any further.
I too have not heard about this sotrupai before this. Can you get back to me on the same?
Thank you and bye.