How about breast fat grafting?

I am looking into breast fat grafting. I am curious whether the results are certain and if there are any side effects. Also, recently, I have been reading a lot about stem cell breast fat grafting in the information and reviews I found, and I wonder what the difference is between regular breast fat grafting and stem cell breast fat grafting. I heard that stem cell breast fat grafting has higher engraftment rates and lasts longer, but how long does it typically last? I want to know in detail about stem cell breast fat grafting.