What kinds of bone plates used in cranio-facial surgery?

Usually titanium. Plates and screws used in craniofacial surgery are usually titanium. Some are stainless steel or cobalt-chromium. There are also resorbable (absorbed by the body over time) non-metal plates and screws.
Facial Bone Plates. Cranio-facial surgery in infants can be performed with absorbable plates and screws. Procedures in older children and adults are usually performed with titanium plates and screws that remain in place unless they cause problems that require their removal.