Fun CEREC case I did this week. Conservative veneer preps with 0.5 mm subgingival margins and flat top (onlay) extension on premolars. Tissue retraction accomplished with Expasyl...3 minute placement and then rinse. Vita Scan Spray, two coats with air dry after each coat and then scan.  As observed on the HD black/white screen image, the margin exposure is impeccable.  This product is incredible...has a varnish like characteristic without caking at the margins. Vita Scan Spray reflective characteristics provides a new dimensional ease for optical impression refinement. Will post finished photos after tissues heal.