how to establish point to point correspondence between 3D face scans?

Hi every body, I have a database of 500 3D face scans as shape and texture vectors of each face. shape vectors contain x,y,z of vertices and texture vectors contain R,G,B values of each vertex. but the number of vertices of each face is difference. How can I establish a reference face and then create full correspondence between all of these faces to have have equal number of vertices with correspondence. Thanks in advance