Green speeds are generally slower for 3-4 days following aerification and topdressings because the sand significantly dulls the mower blades. Eventually the sand works its way off of the turf surface.
Below are the processes that we use during the aerification process.
Sand is spread over the green's surface
The greens are rolled to help level and firm the surfaces. Aerification generally softens the surface for an initial period until the holes heal and the surface firms.