There's no different between both words. If you use it like a possessive pronoun the current rule says that you don't need to put a tilde in the first "e" (este), just write "este es mi coche" or "este es mi hermano", "estos son mis amigos" etc.
Another different word is Este, when you are talking about the north, south, east (EAST) or west.
I hope I was able to help you! (and sorry for my bad English! )