About GKG Ortho The people of Pittsburgh, Wexford, and Cranberry, PA trust the doctors, technicians, and staff at GKG Orthodontics to provide excellent service in a friendly environment. Drs. John Grady, Dan Kastner, and Matthew Gornick apply the same high standard of treatment to every patient, crafting beautiful smiles for people of all ages. We know you have many options for orthodontic care and we’re delighted that you chose our practice for your family.