the difference between Site-Directed Mutagenesis and Site-Saturation Mutagenesis - (Mar/25/2015 )

What's the difference between Site-Directed Mutagenesis and Site-Saturation Mutagenesis? What's the most appropriate one for Reducing homology between two related proteins?

I think the most appropriate one for Reducing homology between two related proteins is 

Site-Saturation Mutagenesis, but I'm not quite sure about it.