[Histonet] Immunohistochemistry on mouse teeth

[Horn, Diane A]

I am currently doing IHC on develping mouse teeth and I am getting only backgroung staining.  The tissues are fixed O/N in 4% paraformaldehyde @4 degrees and embedded in paraffin.  I have cut my sections @ 4um.  I have tried HIER with Vector unmasking solution (boiling) for 2 minutes and using a kit for PCNA from Zymed.  Has anyone done IHC on teeth that could give me some advice on what to try next?
 
Thanks!
Diane