Russ,
        as I don't remember seeing comments about your question re IHC
and ground sections I will take a a stab at it.
Where precisely does this PGM believe that the alpha 2HS protein is
located? I am assuming that he believes that it is either in the matrix
of the dentin, in the predentin or in the dentinal tubules. I cannot see
the rationale therefore for using ground sections. The process of
slicing and grinding to thickeness will have damaged the tissue to a
certain extent and may have allowed some of the glycoprotein  to be
removed (although this is doubtful).
Using EDTA to open up tubules is not useful unless he thinks the
glycoprotein is located within the tubules. Abrasive on the surface of
the section should not be a problem, I am assuming that it is
carborundum or diamond powder?
I see no reason why the section cannot be completely demineralized to
allow the IHC reagents to gain access to the matrix  and the alpha 2HS
glycoprotein as the mineral salts present in the ground section may well
interfere with the IHC reaction.
The current use of IHC on ground sections seems to be ill thought out by
this individual. I recommend that you send him on a fact finding mission
to look for the origin of this technique. I hear that there are several
caves in Tibet which may well hold clues to the use of ground sections
and IHC.
Barry